Elbow prosthesis

ABSTRACT

A joint prosthesis is provided and may include first and second stem structures and first and second bearing members. The first stem structure may include a generally U-shaped portion having first and second legs. The second stem structure may include first and second bearing surfaces. The first bearing member may be removably coupled to the first leg and may include a first laterally facing bearing surface rotatably contacting the first bearing surface. The second bearing member may be removably coupled to the second leg and may include a second laterally facing bearing surface rotatably contacting the second bearing surface. The first laterally facing bearing surface may be disposed between the first leg and a first lateral side of the second stem. The second laterally facing bearing surface may be disposed between the second leg and a second lateral side of the second stem. The second lateral side may oppose the first lateral side.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/780,424, filed on May 24, 2010, which is a continuation-in-part ofU.S. patent application Ser. No. 12/562,616, filed on Sep. 18, 2009,which is a continuation-in-part of U.S. patent application Ser. No.12/391,904, filed on Feb. 24, 2009, which is a continuation-in-part ofU.S. patent application Ser. No. 11/384,943 filed on Mar. 17, 2006 (nowU.S. Pat. No. 8,585,768), which is a continuation-in-part of U.S. patentapplication Ser. No. 10/333,140 filed on Jan. 15, 2003 (now U.S. Pat.No. 7,247,170), which is a National Stage of International ApplicationNo. PCT/US01/22338 (published as WO 02/05728), filed Jul. 17, 2001,which claims priority to U.S. Provisional Application No. 60/219,103filed Jul. 18, 2000. Each of these applications are incorporated hereinby reference.

U.S. patent application Ser. No. 11/780,365 filed on Sep. 19, 2007 whichis now U.S. Pat. No. 7,625,406 and U.S. patent application Ser. No.11/780,370 filed on Sep. 19, 2007 which is now U.S. Pat. No. 7,604,666disclose related subject matter. These applications are alsoincorporated herein by reference.

FIELD

The present teachings relate generally to prosthetic devices used inarthroplasty and more particularly to a modular elbow prosthesis.

BACKGROUND

The present teachings relate generally to prosthetic devices used inarthroplasty and more particularly to a modular elbow prosthesis.

Linked or constrained elbow prostheses are known which comprise simplehinge arrangements, one component of which is attached to the end of thehumerus and the other component of which is attached to the end of theulna. The humeral component includes a shaft, which is cemented into aprepared cavity in the end of the humerus, and the ulnar componentincludes a shaft, that is cemented to the end of the ulna. Thecomponents of the prosthesis are connected together by means of a hingepin so that the prosthesis allows a single degree of freedom of movementof the ulna relative to the humerus.

One example of a linked elbow prostheses is disclosed in U.S. Pat. No.6,027,534 to Wack et al. In several respects, the linked embodiment ofthe '534 patent is typical of the designs for linked elbow prostheses inthat it includes a humeral stem that terminates at a yoke at its distalend, a bearing component, a retaining pin and an ulna stem. The bearingcomponent includes an oversized hole that is aligned with thelongitudinal axis of the bearing and adapted to accept the retaining pinin a slip-fit condition. The distal end of the bearing component iscoupled to the ulna stem. Despite the relatively widespread use ofdesigns of this type, several drawbacks have been noted.

One significant drawback concerns the assembly of the elbow prosthesisafter the surgeon has cemented the humeral and ulna stems to theirrespective bones. In using such conventionally configured linked elbowprosthesis devices, it is frequently necessary for the surgeon to drilla fairly large hole through the humerus so that the retaining pin may beinserted to the yoke of the humeral stem and the humeral bearingcomponent. As a high degree of accuracy is typically required to ensureproper alignment between the hole in the humerus and the hole in theyoke of the humeral stem, a significant cost can be associated with thisstep in the installation of an elbow prosthesis due to the cost of thetooling used and the amount of time required to complete this step. Theother method for attaching the prosthetic device includes inserting thedevice in its linked condition or placing the remaining piece into theyoke prior to fully seating the humeral component into the bone. Thislater method is typically somewhat difficult, given the limited amountof joint space that is available and the time constraints associatedwith the use of a PMMA bone cement.

Unlinked, or unconstrained, elbow prostheses are known which are similarto linked elbow prostheses but do not have a specific component whichmechanically couples the humeral and ulnar stems together. Rather, theprosthetic device is held together by the patient's natural softtissues. One example of an unlinked elbow prostheses is also disclosedin U.S. Pat. No. 6,027,534 to Wack et al. In several respects, theunlinked embodiment of the '534 patent is similar to the linkedembodiment discussed above in that it includes a humeral stem thatterminates at a yoke at its distal end, a humeral bearing component, aretaining pin, an ulnar bearing component and a ulnar stem. The outersurface of the humeral bearing is contoured to match the contour of theulnar bearing component. Despite the relatively widespread use ofdesigns of this type, several drawbacks have been noted.

For instance, a retaining pin that is transverse to the longitudinalaxis of the patient is employed, thereby making its removal difficult ifa bearing need to be replaced.

SUMMARY

An elbow prosthesis constructed in accordance to one example of thepresent teachings can include a first stem structure that is operable tobe positioned in a first bone of a joint. The first stem structure caninclude a first stem portion and a cage structure. The first stemportion may be operable to be positioned in the first bone. The cagestructure can be formed generally between an inner sidewall and an outersurface. The stem portion can have opposing surfaces that define adisconnect formed entirely through the cage structure from the innersidewall to the outer surface. A first bearing component can have anexterior cage opposing surface. The first bearing component can beselectively inserted into the cage structure from an insertion positionto an installed position. A fastener can be threadably advanced into anengaged position with the cage structure to reduce a gap defined betweenthe opposing surfaces of the disconnect while radially contracting thecage structure around the first bearing.

According to additional features, at least one of opposing surfaces ofthe disconnect is non-linear from the inner sidewall to the outersurface. The inner sidewall of the cage structure can have a firstgroove and the exterior cage opposing surface can have a second groovethat opposes the first groove in the installed position. A lock ring canpartially nest within each of the first and second grooves in theassembled position.

According to still other features, the cage structure can include atleast one tabbed entry formed on the inner sidewall that slidablyaccepts at least one tab formed on the exterior cage opposing surface ofthe first bearing component in the installed position. The at least onetab and tab entry respectively can cooperate to inhibit rotation of thefirst bearing around the inner sidewall of the cage structure in theassembled position.

According to additional features, the inner sidewall can have a firstV-shaped cross-section. The exterior cage opposing surface of the firstbearing component can have a second V-shaped cross-section thatcooperatively engages the first V-shaped cross-section to inhibitmedial/lateral movement of the first bearing in the installed position.A second bearing component can be provided that is associated with asecond stem structure. The second bearing component can be operable tocooperatively rotate with the first bearing component. The first stemstructure can be adapted to be implanted into one of a humerus or ulna.The second stem structure can be adapted to be implanted into the otherof the humerus and ulna.

An elbow prosthesis according to another example of the presentteachings can include a stem structure that is operable to be positionedinto a bone of a joint. The stem structure can include a stem portionand C-shaped body portion. The stem portion can be operable to bepositioned in the bone. The C-shaped body portion can have a firstretaining mechanism formed thereon. The elbow prosthesis can furthercomprise an articulating component that has a second retaining mechanismformed thereon. The articulating component can be rotatably advancedfrom an insertion position to an assembled position, such that the firstand second retaining mechanisms cooperatively interlock to inhibitmedial/lateral movement of the articulating component relative to theC-shaped body portion of the stem structure. The first retainingmechanism can comprise outwardly extending rails that are formed on theC-shaped body portion. The first retaining mechanism can furthercomprise a stop having stop surfaces provided on one end of the rails.The second retaining mechanism can comprise a channel having a geometrythat cooperatively receives the rails of the C-shaped body portion. Thearticulating component can comprise a catch having catch surfaces thatengage the stop surfaces in the assembled position. A plate and afastener can further be provided. The fastener can extend through apassage in the plate that threadably couples to the stem portion. Theplate can inhibit rotation of the articulating component from theassembled position to the insertion position. A plurality ofarticulating components can be provided each having various geometries.One of the articulating components from the plurality can be selectedand coupled to the stem structure according to a given patient'sspecific needs.

An elbow prosthesis constructed in accordance to other features of thepresent teachings can include a stem structure operable to be positionedin a bone of a joint. The stem structure can include a stem portion anda C-shaped body portion. The stem portion can be operable to bepositioned in the bone. The C-shaped body portion can have a firstretaining mechanism thereon. The elbow prosthesis can further comprisean articulating component having a second retaining mechanism formedthereon. One of the first and second retaining mechanisms comprises arail and the other of the first and second mechanisms comprises agroove. The articulating component is advanced from an insertionposition to an installed position, such that the first and secondretaining mechanisms cooperatively interlock to inhibit medial/lateralmovement of the articulating component relative to the C-shaped bodyportion of the stem structure.

According to other features, the articulating component can comprise abearing portion and a rail. The rail can have a first end that includesa plate and a second end that includes a hook. The plate can include aneyelet adapted to receive a fastener therethrough. The fastener canthreadably couple the articulating component to the stem structure. Thehook can cooperatively engage an end of the stem portion at the groove.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

Additional advantages and features of the present teachings will becomeapparent from the subsequent description and the appended claims, takenin conjunction with the accompanying drawings, wherein:

FIG. 1 is an exploded perspective view of a linked prosthetic joint kitconstructed in accordance with the teachings of a first aspect of thepresent teachings;

FIG. 1A is an exploded perspective view of a linked prosthetic joint kitsimilar to that of FIG. 1 but constructed in accordance with a firstalternate embodiment of the first aspect of the present teachings;

FIG. 2 is a longitudinal cross-sectional view of the linked prostheticjoint kit of FIG. 1 implanted in the arm of a person;

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is an exploded perspective view of an unlinked prosthetic jointkit constructed in accordance with the teachings of a first aspect ofthe present teachings;

FIG. 5 is a longitudinal cross-sectional view of the unlinked prostheticjoint kit of FIG. 4 implanted in the arm of a person;

FIG. 6 is an exploded plan view of a linked prosthetic joint kitconstructed in accordance with a second alternate embodiment of thefirst aspect of the present teachings;

FIG. 7 is an enlarged portion of the linked prosthetic joint kit of FIG.6;

FIG. 8 is an exploded plan view of a linked prosthetic joint kitconstructed in accordance with a third alternate embodiment of the firstaspect of the present teachings;

FIG. 9 is a exploded side elevation view of a portion of a joint kitconstructed in accordance with the teachings of a second aspect of thepresent teachings;

FIG. 10 is an exploded side elevation view of a portion of a joint kitconstructed in accordance with a first alternate embodiment of thesecond aspect of the present teachings;

FIG. 11 is an exploded side elevation view of a portion of a joint kitconstructed in accordance with a third alternate embodiment of thesecond aspect of the present teachings;

FIG. 12 is a longitudinal cross-sectional view of a portion of a jointkit constructed in accordance with a fourth alternate embodiment of thesecond aspect of the present teachings;

FIG. 13 is an exploded side elevation view of a portion of a joint kitconstructed in accordance with a fifth alternate embodiment of thesecond aspect of the present teachings;

FIG. 14 is a cross-sectional view taken along the line 14-14 of FIG. 13;

FIG. 15 is a cross-sectional view of a portion of a joint kitconstructed in accordance with a sixth alternate embodiment of thesecond aspect of the present teachings;

FIG. 16 is an exploded side elevation view of a portion of linkedprosthetic joint kit constructed in accordance with the teachings ofvarious embodiments of a third aspect of the present teachings;

FIG. 17 is a cross-sectional view taken along the line 17-17 of FIG. 16;

FIG. 18 is a cross-sectional view taken along the line 18-18 of FIG. 16;

FIG. 19A through 19D are side elevation views of bearing insertsconstructed with varying degrees of varus/valgus constraint;

FIG. 20A is an exploded side elevation view of a portion of a linkedprosthetic joint kit constructed in accordance with the teachings of afirst alternate embodiment of the third aspect of the present teachings;

FIG. 20B is an exploded side elevation view of a portion of a linkedprosthetic joint constructed in accordance with the teachings of secondalternate embodiment of the third aspect of the present teachings;

FIG. 20C is a side view of an alternately constructed pin for linkingthe stem structures of the second alternate embodiment of the thirdaspect of the present teachings;

FIG. 21 is a bottom plan view of a portion of the linked prostheticjoint kit of FIG. 20A illustrating the bearing insert in greater detail;

FIG. 22 is a side elevation view of a portion of the linked prostheticjoint kit of FIG. 20A illustrating the clip member in greater detail;

FIG. 23 is a longitudinal cross-sectional view of a linked prostheticjoint kit constructed in accordance with the teachings of a variousembodiment of a fourth aspect of the present teachings;

FIG. 24 is a top plan view of the linked prosthetic joint kit of FIG.23;

FIG. 25 is an exploded top plan view of a linked prosthetic joint kitconstructed in accordance with the teachings of a various embodiment ofa fifth aspect of the present teachings;

FIG. 26 is a longitudinal cross-sectional view of the linked prostheticjoint kit of FIG. 25;

FIG. 27 is a longitudinal cross-sectional view similar to that of FIG.2, but illustrating the stem with an integrally-formed flange forcompressing a bone graft;

FIG. 28 is a side view illustrating a stem with an integrally-formed,resilient flange for compressing a bone graft;

FIG. 29 is a longitudinal cross-sectional view similar to that of FIG.2, but illustrating the stem of FIG. 28;

FIG. 30 is a longitudinal cross-sectional view similar to that of FIG.29, but illustrating the resilient flange as being fixedly but removablycoupled to the stem;

FIG. 31 is a partially broken-away exploded perspective viewillustrating an alternative coupling means for coupling the modularflange to the stem;

FIG. 32 is a longitudinal cross-sectional view similar to that of FIG.2, but illustrating the alternative coupling means of FIG. 31;

FIG. 33 is a view similar to that of FIG. 31 but illustrating a secondalternative coupling means;

FIG. 34 is a view similar to that of FIG. 31 but illustrating a thirdalternative coupling means;

FIG. 35 is a longitudinal cross-sectional view similar to that of FIG.2, but illustrating the alternative coupling means of FIG. 34;

FIG. 36 is an exploded perspective view of a prosthesis according tovarious embodiments;

FIG. 37 is a detailed cross-sectional view of an assembled prosthesisaccording to various embodiments;

FIG. 38 is an exploded plan view of a prosthesis according to variousembodiments;

FIG. 39 is a detailed environmental view of a prosthesis implanted in ananatomy according to various embodiments;

FIG. 40 is a perspective view of a stem structure with a modular flange;

FIG. 41 is a perspective view of a stem structure with a modular flange;

FIG. 42 is an exploded perspective view of an elbow prosthesis,according to various embodiments;

FIG. 43 is a detail plan view of a first and second fastener;

FIG. 44 is a detail cross-sectional view of the elbow prosthesis of FIG.42 along line 44-44;

FIG. 45 is an exploded perspective view of a stem structure with modularbearing member;

FIG. 46 is a plan view of an assembled stem structure of FIG. 45 in afirst orientation;

FIG. 47A is a plan view of an assembled stem structure of FIG. 45 in asecond orientation;

FIG. 47B is a cross-sectional view of the assembled stem structure ofFIG. 47A along line 47B-47B;

FIG. 48 is an exploded perspective view of a stem structure with modularbearing member;

FIG. 49 is a plan view of an assembled stem structure of FIG. 48 in afirst orientation;

FIG. 50A is a plan view of an assembled stem structure of FIG. 48 in asecond orientation;

FIG. 50B is a cross-sectional view of the assembled stem structure ofFIG. 50A along line 50B-50B;

FIG. 51 is an exploded perspective view of a stem structure with modularbearing member;

FIG. 52A is a plan view of an assembled stem structure of FIG. 51;

FIG. 52B is a cross-sectional view of the assembled stem structure ofFIG. 52A along line 52B-52B;

FIG. 53 is a perspective view of a stem assembly constructed inaccordance to additional features of the present teachings;

FIG. 54 is an exploded perspective view of the stem assembly of FIG. 53;

FIG. 55 is a cross-sectional view of the stem assembly showing a bearingmember in an insertion position relative to a stem member;

FIG. 56 is a cross-sectional view of the stem assembly of FIG. 55 andshown during assembly of the bearing into a cage of the stem component;

FIG. 57 is a cross-sectional view of the stem assembly of FIGS. 55 and56 and shown with the bearing in an assembled position relative to thestem component;

FIG. 58 is a cross-sectional view of the stem assembly prior toinsertion of a fastener into the stem component;

FIG. 59 is a cross-sectional view of the stem assembly of FIG. 58 andshown with the fastener threadably assembled;

FIG. 60 is a perspective view of a stem component constructed inaccordance to additional features;

FIG. 61 is a perspective view of a stem assembly constructed inaccordance to additional features of the present teachings;

FIG. 62 is an exploded perspective view of the stem assembly of FIG. 61and shown with an alternate bearing;

FIG. 63 is a cross-sectional view of the stem component and bearing ofFIG. 62 and shown in an insertion position;

FIG. 64 is a cross-sectional view of the bearing and stem component ofFIG. 63 and shown with the bearing partially inserted into a cagestructure of the stem component during an assembly step;

FIG. 65 is a cross-sectional view of the bearing and stem component ofFIGS. 63 and 64 and shown with the bearing in an assembled positionrelative to the stem component;

FIG. 66 is a cross-sectional view of the stem assembly of FIG. 62 andshown with a fastener being threadably assembled into the stemcomponent;

FIG. 67 is a cross-sectional view of the stem assembly of FIG. 66 andshown with a fastener threaded into the stem component in an assembledposition;

FIG. 68 is a perspective view of a modular unlinked ulnar stem assemblyconstructed in accordance to one example of the present teachings;

FIG. 69 is an exploded perspective view of portions of the ulnar stemassembly of FIG. 68;

FIGS. 70-72 is an assembly sequence showing an articulating component orbearing being selectively secured to the stem component;

FIG. 73 is a perspective view of a modular unlinked ulnar stem assemblyconstructed in accordance to additional features of the presentteachings;

FIG. 74 is an exploded perspective view of portions of the ulnar stemassembly of FIG. 73;

FIG. 75 is an exploded perspective view of portions of an unlinked ulnarstem assembly having a retaining mechanism constructed in accordance toadditional features of the present teachings;

FIGS. 76-77 are an assembly sequence showing the modular articulatingcomponent being coupled to the stem component according to one example;

FIGS. 78-79 are an assembly sequence showing an articulating componentand stem component according to additional features and illustrating anexemplary sequence of coupling the articulating component to the stemcomponent;

FIGS. 80 and 81 illustrate an exemplary assembly sequence of anotherunlinked ulnar stem assembly according to additional features;

FIGS. 82 and 83 illustrate an exemplary assembly sequence of anotherunlinked ulnar stem assembly according to additional features;

FIG. 84 is a perspective view of an exemplary bearing removal tool kitconstructed in accordance to one example of the present teachings;

FIG. 85 is a medial perspective view of an exemplary ulna stem componentand bearing member shown with a first tool of the bearing removal toolkit slidably inserting extractor pins according to one example;

FIG. 86 is a detailed perspective view of a pair of extractor pins afterbeing located into respective depressions of the bearing member by thefirst tool;

FIGS. 87 and 88 are an exemplary sequence illustrating a second toolused to further advance the extractor pins around the lock ring tocompress the lock ring into the groove of the ulna bearing;

FIGS. 89 and 90 are an exemplary sequence illustrating an extractorplate used to concurrently advance a plurality of extractor pins acrossthe lock ring to compress the lock ring into the groove of the ulnabearing according to additional features; and

FIGS. 91 and 92 are an exemplary sequence illustrating a third toolurging the bearing member out of the cage structure of the ulna stemaccording to one example of the present teachings.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

With reference to FIGS. 1, 2 and 3 of the drawings, a linked prostheticjoint device constructed in accordance with the teachings of a firstaspect is generally indicated by reference number 10. Although theparticular prosthesis illustrated and discussed relates to a prosthesisfor use in reconstructing an elbow, it will be understood that theteachings have applicability to other types of linked and unlinkedprosthetic devices. As such, the scope of the present teachings will notbe limited to applications involving elbow prosthesis but will extend toother prosthetic applications.

In the particular embodiment illustrated, linked prosthetic joint 10 isshown to include a first stem structure 12, a second stem structure 14,a first bearing component 16, a second bearing component 18, a modularflange 20 and a tissue fastener 22. First stem structure 12 includes aproximal portion 30 and a distal portion 32. Proximal portion 30includes a stem member 34 which is adapted to fit within the medullarycanal 36 of a humerus 38. Distal portion 32 includes a generallyU-shaped member 40 which is fixedly coupled to the distal end ofproximal portion 30. U-shaped portion 40 includes a pair of spaced-apartlegs or furcations 42. A threaded fastener aperture 44 extendsperpendicularly through each of the furcations 42.

Second stem structure 14 includes a distal portion 50 which is adaptedto fit within the medullary canal 52 of an ulna 54. Second stemstructure 14 also includes a proximal portion 56 which is coupled tosecond bearing component 18. In the particular embodiment illustrated,second bearing component 18 is fixedly coupled to second stem structure14. However, second bearing component 18 may also be releasably coupledto second stem structure 14 as shown in FIGS. 9 through 12.

First bearing component 16 includes a pair of condyle portions 60, a pinportion 62 and a pair of fasteners 64. Condyle portions 60 and pinportion 62 are formed from a suitable material, such as cobalt chromiumalloy. Each condyle portion 60 is shown to include a spherically-shapedbearing portion 66, slotted aperture 68, a pin aperture 70 and amounting aperture 72. The pair of spherically shaped bearing portions 66collectively form a first bearing surface. Pin aperture 70 is sized toreceive an end of pin portion 62 to permit pin portion 62 to slidinglyengage condyle portions 60. Pin 62 can also be fixedly coupled with oneof said condyle portion 60 and slidingly engage second of said condyleportion 60. Each of the slotted apertures 68 is sized to slidinglyengage one of the furcations 42.

Second bearing component 18 is shown to include a cage portion 80 whichis fixedly coupled to the proximal portion 56 of second stem structure14 and a bearing member 82 which is fixedly coupled to the cage portion80. Bearing member 82 includes a pair of spherical bearing portions 84which are configured to engage the spherically shaped bearing portions66 of the condyle portions 60. The pair of spherical bearing surfaces 84collectively form a second bearing surface that mates with the firstbearing surface. Bearing member 82 also includes a through hole 86 whichis adapted to receive pin portion 62, preferably without transmittingload therebetween (i.e., pin portion 62 preferably does not contact thesurfaces of through hole 86). In the particular embodiment illustrated,bearing member 82 is fabricated from polyethylene which has been moldedto cage portion 80. Alternatively, bearing member 82 may be fabricatedfrom any other appropriate material such as a stainless steel, ceramic,pyrolytic carbon, cobalt chrome (CoCr) etc.

To use linked prosthetic joint 10, first stem structure 12 is implantedin humerus 38 such that proximal portion 34 is located in the medullarycanal 36 of the humerus 38 as shown in FIG. 2. Second stem structure 14is similarly implanted in ulna 54 such that distal portion 50 is locatedin the medullary canal 52. Pin portion 62 is next inserted to the pinaperture 70 of one of the condyle portions 60 and the opposite end ofpin portion 62 is placed through hole 86 and into the pin aperture 70 ofthe other one of the condyle portions 60. Second bearing component 18 ispositioned adjacent the distal portion 32 of first stem structure 12,furcations 42 are aligned to their respective slotted aperture 68 andcondyle portions 60 are slidingly engaged to furcations 42. Fasteners 64are inserted through their respective mounting apertures 72 andthreadably engaged to their threaded fastener aperture 44. When fullyseated, each of the fasteners 64 extends through its respectivefurcation 42 to prevent condyle portion 60 from rotating relative to thefurcation 42. At this point, first and second bearing components 16 and18 hingedly couple first and second stem structures 12 and 14 togetherin a linked or constrained manner.

Construction of linked prosthetic joint 10 in this manner is highlyadvantageous in that it permits the surgeon to insert the first andsecond stem structures 12 and 14 prior to or after assembling linkedprosthetic joint 10, as well as permits linked prosthetic joint 10 to beassembled in a relatively small space as compared to most of the otherprosthetic joints that are known in the art. Furthermore, the sphericalconfiguration of first and second bearing surfaces 66 and 84 permits theload which is transmitted through linked prosthetic joint 10 to bespread out over a relatively large area, rather than concentrated at asingle point or over a line of contact to thereby improve the durabilityof linked prosthetic joint 10.

Modular flange 20 may be employed to increase the resistance of firststem structure 12 to rotation within medullary canal 36. In FIGS. 1 and2, modular flange 20 is shown to include an internally threaded fastener90, and a unitarily formed flange structure 92 having a mount member 94and a flange member 96. Mount member 94 includes a locating cylinder 94a which is fixedly coupled to flange member 96 at its base and anexternally threaded fastener 94 b which is coupled to an opposite sideof locating cylinder 94 a. A mounting hole 98, which is sized to receivefastener 94 b, extends through internally threaded fastener 90. A bore100 formed through the base 102 of U-shaped portion 40 has a firstportion 104 which is tapered at one end to engage the edges ofinternally threaded fastener 90 and second portion 106 which is counterbored at the other end to engage the locating cylinder 94 a of mountmember 94. Internally threaded fastener 90 is threadably engaged tofastener 94 b to fixedly but removably couple modular flange 20 to firststem structure 12.

Modular flange 20 may be employed to generate a clamping force whichclamps a portion 108 of the humerus 38 between the proximal portion 34of the first stem structure 12 and the flange member 96. Preferably, abone graft 110 is employed in conjunction with modular flange 20 suchthat the clamping force produced by modular flange 20 is alsotransmitted to bone graft 110 to promote the attachment of bone graft110 to humerus 38 and the subsequent growth of bone graft 110. Thoseskilled in the art will understand that alternatively, a flange (notshown) which is unitarily formed with first stem structure 12 may beincorporated into linked prosthetic joint 10 to thereby increase theresistance of first stem structure 12 to rotation within medullary canal36. However, a flange which is unitarily formed with first stemstructure 12 could not be employed to generate a clamping force whichclamps a portion 108 of the humerus 38 between the proximal portion 34of the first stem structure 12 and the flange.

Tissue fastener 22 is shown in FIGS. 1 and 2 to be a device forattaching soft tissue, such as tendons 130, to linked prosthetic joint10. In this regard, the specific configuration of tissue fastener isbeyond the scope of this disclosure. Examples of suitable tissuefasteners are discussed in U.S. Pat. Nos. 5,380,334, 5,584,835,5,725,541, 5,840,078 and 5,980,557 which are hereby incorporated byreference as if fully set forth herein.

In the particular embodiment illustrated, tissue fastener 22 is shown toinclude a tissue clamp 132 and a threaded fastener 134. Tissue clamp 132includes an annular base 136 and a pair of prongs 138. Prongs 138 areforced through the soft tissue (e.g., tendons 130). Threaded fastener134 is inserted through a hole in base 136 and threadably engaged tosecond stem structure 14 to fixedly but releasably couple tissuefastener 22 and the soft tissue to second stem structure 14. Thoseskilled in the art will understand that tissue fastener 22 may also beused in conjunction with first stem structure 12.

In FIG. 1A, a linked prosthetic joint device constructed in accordancewith the teachings of an alternate embodiment of the first aspect of thepresent teachings is generally indicated by reference numeral 10 a.Linked prosthetic joint 10 a is shown to include first stem structure12, second stem structure 14, first bearing component 16 a, secondbearing component 18 a, modular flange 20 and tissue fastener 22.

First bearing component 16 a is similar to first bearing component 16 inall respects except that it is unitarily formed. Accordingly, pinportion 62 a is not removable form condyle portions 60 a. Second bearingcomponent 18 a is similar to second bearing component 18 in all respectsexcept that an insertion aperture 150 extends form through hole 86 aoutwardly through bearing member 82 a and cage portion 80 a.Accordingly, insertion aperture 150 renders the area of second bearingsurface 84 a somewhat smaller than second bearing surface 84. Secondbearing surface 84 a is otherwise identical to second bearing surface84.

To use linked prosthetic joint device 10 a, first and second stemstructures 12 and 14 are initially inserted to the humerus and ulna andfirst bearing component 16 a is fastened to the first stem structure 12using techniques similar to that discussed above for prosthetic jointdevice 10. First bearing component 16 a is then positioned adjacentsecond bearing component 18 a such that pin portion 62 a is in insertionaperture 150. Pin portion 62 a is then forced toward through hole 86 a.The distal end 152 of insertion aperture 150 is smaller than pin portion62 a to permit bearing member 82 a to engage pin portion 62 a in a snapfit manner, so as to inhibit the unintentional withdrawal of pin portion62 a from through hole 86 a. As discussed above, through hole 86 a ispreferably larger in diameter than pin portion 62 a. At this point,first and second bearing components 16 a and 18 a hingedly couple firstand second stem structures 12 and 14 together in a linked manner.

In FIGS. 4 and 5, an unconstrained or unlinked prosthetic joint deviceconstructed according to a first aspect of the present teachings isgenerally indicated by reference number 10′. Unlinked prosthetic joint10′ is shown to include a first stem structure 12, a second stemstructure 14, a first bearing component 16′, a second bearing component18′, a modular flange 20 and a tissue fastener 22. Unlinked prostheticjoint 10′ is shown to be operatively associated with a humerus 38′ andan ulna 54′ (FIG. 5), but those skilled in the art will understand thatthe teachings of the present teachings have application to prostheticjoints for other applications and as such, the scope of the presentteachings will not be limited to elbow joints.

First bearing component 16′ is similar to first bearing component 16 inthat it includes a pair of condyle portions 60′ and a pin portion 62′.However, first bearing component 16′ is preferably unitarily formed withpin portion 62′ extending between the spherically-shaped bearingportions 66′ and fixedly coupling the spherically-shaped bearingportions 66′ thereto. Like first bearing component 16, each of thecondyle portions 60′ of first bearing component 16′ includes a slottedaperture 68 and a fastener aperture 72. Spherically shaped bearingportions 66′ collectively form a first bearing surface. Like firstbearing component 16, first bearing component 16′ may be made from anyappropriate bearing material, such as cobalt chromium alloy.

Second bearing component 18′ is similar to second bearing component 18in that it includes a cage portion 80′ which is fixedly coupled to theproximal portion 56 of second stem structure 14 and a bearing member 82′which is fixedly coupled to the cage portion 80′. For purposes ofclarity, bearing member 82′ has not been shown in cross section in FIG.5. Bearing member 82′ includes spherical bearing surfaces 84′ which areadapted to engage the spherically-shaped bearing portions 66′ of thecondyle portions 60′. The pair of bearing surfaces 84′ collectively forma second bearing surface that mates with the first bearing surface.Bearing member 82′ also includes a raised portion 160 which is adjacentthe spherical bearing surfaces 84′ and configured to clear pin portion62′, preferably without transmitting load therebetween (i.e., pinportion 62′ preferably does not contact the surfaces of raised portion160). In the particular embodiment illustrated, bearing member 82′ isfabricated from polyethylene which has been molded to cage portion 80.Alternatively, bearing member 82′ may be fabricated from any otherappropriate material such as a cobalt chromium alloy, ceramics, orstainless steel.

To use unlinked prosthetic joint 10′, first stem structure 12 isimplanted in humerus 38′ such that proximal portion 34 is located in themedullary canal 36′ as shown in FIG. 5. Second stem structure 14 issimilarly implanted in ulna 54′ such that distal portion 50 is locatedin the medullary canal 52′. First bearing component 16′ is nextpositioned adjacent the distal portion 32 of first stem structure 12 andfurcations 42 are engaged to slotted apertures 68. Fasteners 64 areinserted through their respective mounting apertures 72 and threadablyengaged to their threaded fastener aperture 44. When fully seated, eachof the fasteners 64, extends through its respective furcation 42 toprevent its associated condyle portion 60′ from rotating relative tothereto. The proximal end of the ulna 54′ is positioned adjacent thedistal end of the humerus 38′ such that the pin portion 62′ is proximatethe raised portion 160 and the spherically-shaped bearing portions 66′of the condyle portions 60′ engage the spherical bearing surface 84′. Atthis point, first and second bearing components 16′ and 18′ are coupledtogether in an unconstrained or unlinked manner (i.e., held in positionby the soft tissues of the elbow). Construction of unlinked prostheticjoint 10′ in this manner provides many of the same advantages asmentioned above for linked prosthetic joint 10, such as the ability offirst and second bearing surfaces 16′ and 18′ to spread out the loadthat is transmitted through unlinked prosthetic joint 10′ over arelatively large area, rather than concentrate the load at a singlepoint or over a line of contact to thereby improve the durability ofunlinked prosthetic joint 10′.

As a surgeon may not always know prior to beginning an operation whethera patient would be better served by a linked or an unlinked jointprosthesis and as it is also occasionally necessary to convert anunlinked joint prosthesis to a constrained joint prosthesis, or viceversa, after implementation and use for a period of time, it is highlydesirable that the joint prosthesis be modular so as to provide thesurgeon with a high degree of flexibility which may be achieved in arelatively simple and cost-effective manner.

In FIGS. 6 and 7, a linked prosthetic joint constructed in accordancewith a second aspect of the present teachings is generally indicated byreference numeral 10 b. Linked prosthetic joint 10 b is shown to includefirst stem structure 12, a third stem structure 180, first bearingcomponent 16, a third bearing component 182. Third stem structure 180 issimilar to second stem structure 14 in that it includes a distal portion184 which is adapted to fit within the medullary canal of an ulna. Theproximal portion 186 of third stem structure 180 is coupled to thirdbearing component 182.

Third bearing component 182 is similar to second bearing component 18 inthat it includes a cage portion 190 and a bearing member 192. Cageportion 190 is fixedly coupled to the proximal portion 186 of third stemstructure 180. Bearing member 192 is fixedly coupled to cage portion190. Bearing member 192 includes a pair of spherical bearing surfaces194 which are configured to engage the spherically-shaped bearingportions 66 of the condyle portions 60 and a through hole 196 which isconfigured to receive pin portion 62, preferably without transmittingload therebetween (i.e., pin portion 62 preferably does not contact thesurfaces of through hole 196). Bearing member 182 also includes alateral buttress 200. Lateral buttress 200 includes a supplementarybearing surface 201 which is configured for receiving a capitellum 202of the humerus 204. In the particular embodiment illustrated, thirdbearing component 182 is fixedly coupled to third stem structure 180 andas such, the combination of the second stem structure 14 and secondbearing component 18 is interchangeable with the combination of thethird stem structure 180 and the third bearing component 182. However,those skilled in the art will understand that second and third bearingcomponents 18 and 182 may also be releasably coupled to a stemstructure, thereby eliminating the need for a third stem structure 180which would otherwise be identical to second stem structure 14. Thoseskilled in the art will also understand that the lateral buttress mayalternatively be coupled directly to the third stem structure 180, beingeither releasably attached thereto or integrally formed therewith.

In FIG. 8, another linked prosthetic joint constructed in accordancewith the teachings of a second aspect of the present teachings isgenerally indicated by reference numeral 10 c. Linked prosthetic joint10 c is shown to include first stem structure 12, second stem structure14, a fourth stem structure 220, second bearing component 18, a fourthbearing component 222 and a fifth bearing component 224. Fourth stemstructure 220 includes a distal end 226 which is adapted to fit withinthe medullary canal of a radius and a proximal end 228 which is fixedlycoupled to fourth bearing component 222. Fourth bearing component 222includes a fourth bearing surface 230.

Fifth bearing component 224 is similar to first bearing component 16 inthat it includes, for example, a pair of condyle portions 60 and a pinportion 62 which permits first and fifth bearing components 16 and 224to be interchangeable. However, fifth bearing component 224 alsoincludes a lateral extension 240 which is adapted to replace at least aportion of the capitellum of the humerus. Lateral extension 240 definesa fifth bearing surface 242 which is configured to mate with fourthbearing surface 230. Preferably, at least a portion of each of thefourth and fifth bearing surfaces 230 and 242 is spherically shaped topermit loads transmitted therebetween to be spread out over a relativelylarge area, rather than be concentrated at a single point or along aline of contact.

In FIG. 9, a portion of a modular prosthetic joint kit constructed inaccordance with the teachings of a second aspect of the presentteachings is generally indicated by reference numeral 10 d. Modularprosthetic joint kit 10 d is shown to include second stem structure 14d, second bearing component 18 d, second bearing component 18 e and afastener 250.

Second bearing components 18 d and 18 e are similar to second bearingcomponents 18 and 18′, respectively, but are shown to be separable fromsecond stem structure 14 d. Second bearing components 18 d and 18 e alsoinclude a keel member 252, a clip member 254 and a fastener aperture 256which are formed in cage portions 80 d and 80 e, respectively. Keelmember 252 extends circumferentially around at least a portion of theperimeter of each of the cage portions 80 d and 80 e between clip member254 and fastener aperture 256. Clip member 254 includes a first portion258 which extends generally perpendicularly outward from its associatedcage portion and a second portion 260 which is coupled to the distal endof first portion 258. Second portion 260 extends generally outwardly andaway from first portion 258. Fastener aperture 256 is located acrossfrom clip member 254 and is sized to receive fastener 250.

Second stem structure 14 d is similar to second stem structure 14 inthat it includes a distal end 50 which is adapted to fit within themedullary canal of an ulna. Second stem structure 14 d also includes aproximal portion 56 d having a keel slot 264, a hook structure 266 andan internally threaded fastener aperture 268. Keel slot 264 is a slotthat is sized to receive keel member 252 in a slip fit manner. Keel slot264 and keel member 252 cooperate to resist relative medial/lateralmotion of cage portion (e.g. 80 d) relative to second stem structure 14d. Hook member 266 is generally U-shaped and defines a clip aperture 270which is sized to receive clip member 254.

To use modular prosthetic joint kit 10 d, the distal end 50 of secondstem structure 14 d is inserted in the medullary canal of the ulna. Themodularity of the prosthetic joint kit 10 d permits the surgeon toassess the patient's elbow to determine if the patient would be betterserved by a linked or an unlinked joint prosthesis. Once a decision hasbeen made as to which type of joint prosthesis would better serve thepatient, the surgeon selects an appropriate one of the second bearingcomponents 18 d and 18 e, places its clip member 254 into the clipaperture 270, pivots the cage portion (i.e. 80 d) toward the proximalend 56 d of the second stem structure 14 d to engage the keel member 252into the keel slot 264, inserts the fastener 250 through the fasteneraperture 256 and threadably engages the fastener 250 to the internallythreaded fastener aperture 268 to fixedly but releasably couple thesecond stem structure 14 d with the selected one of the second bearingcomponents 18 d and 18 e.

Those skilled in the art will understand that second bearing components18 d and 18 e may be coupled to second stem structure 14 d in variousother manners as illustrated in FIGS. 10 through 15. In FIG. 10, secondbearing component 18 f is shown to include a generally L-shaped trayportion 280 which is fixedly coupled to cage portion 80 f. Tray portion280 includes a keel slot 282 and a fastener aperture 284. Keel slot 282is operable for receiving a keel member 286 formed into the proximal end56 f of second stem structure 14 f. Fastener aperture 284 is operablefor receiving a fastener 288 which may be threadably engaged to aninternally-threaded fastener aperture 290 in the proximal end 56 f ofsecond stem structure 14 f to thereby permit second bearing component 18f and second stem structure 14 f to be fixedly but releasably coupled.

When coupled together, keel slot 282 and keel member 286 cooperate toresist relative medial/lateral motion of cage portion 80 f relative tosecond stem structure 14 f. Additionally, tray portion 280 cooperateswith an L-shaped flange 292 to which it abuts to further resist relativerotation between second stem structure 14 f and cage portion 80 f.

In FIG. 11, second bearing components 18 g and 18 h are shown to includea stem member 300 which extends from their respective cage portions 80 gand 80 h. Stem member 300 is engageable with a stem aperture 302 formedinto the proximal end 56 g of second stem structure 14 g. As shown inFIG. 12, stem member 300′ may alternatively be incorporated into theproximal end 56 j of second stem structure 14 j and stem aperture 302′may be formed into cage portion 80 j of second bearing component 18 j.

To provide the surgeon with additional flexibility, second bearingcomponent 18 h is shown in FIG. 11 to be slightly longer than secondbearing component 18 g (i.e., the distances from the centerline ofbearing member 82 to the confronting surface 304 of their respectivecage portions 80 g and 80 h is shorter for second bearing component 18g). This variation between second bearing components 18 g and 18 hpermits the surgeon to adjust the length of prosthesis 10 g to take intoaccount the physical characteristics of the patient's arm.

Modularity may also be incorporated into first stem structure 12 k asshown in FIGS. 13 and 14. First stem structure 12 k is shown to includea stem member 320 and a yoke member 322. The proximal end 324 of stemmember 320 is adapted to fit within the medullary canal of a humerus andthe distal end 326 of stem member 320 terminates at a dovetail aperture328 having a pair of inwardly tapering walls 330 and a tapered retainingwedge 332. An internally threaded fastener aperture 334 extends throughretaining wedge 332. Yoke member 322 is shown to be similar to thedistal end 32 of first stem structure 12 as it includes furcations 42and threaded fastener apertures 44. Yoke member 322 also includes adovetail member 338 having a pair of outwardly tapering surfaces 340, awedge slot 342 and a through hole 344. Dovetail member 338 is configuredto mate with dovetail aperture 328 such that engagement of retainingwedge 332 to the upper surface 346 of wedge slot 342 forces taperedsurfaces 340 against a respective one of the inwardly tapering walls330. A fastener 350 is inserted through hole 344 and threadably engagedto internally threaded fastener aperture 334 to fixedly but releasablycouple yoke member 322 and stem member 320 together.

Referring back to FIG. 11, second bearing components 18 g and 18 h arealso shown to include a pair of tang members 360. Each of the tangmembers 360 extends outwardly from its respective cage portion (i.e., 80g) and in the particular embodiment illustrated, is generallyrectangular in shape. Each of the tang members 360 is sized to engage atang recess 362 in the proximal end 56 g of the second stem structure 14g. Engagement of the tang members 360 into their respective tang recess362 inhibits relative rotation between the second stem structure 14 gand the second bearing components 18 g and 18 h.

In FIG. 15, second bearing component 18 m is shown to have a fasteneraperture 380 which is formed through a bearing member 82 m and cageportion 80 m. Second stem structure 14 m, which is a threaded fastener382 in this embodiment, is disposed through the fastener aperture 380 insecond bearing component 18 m and threadably engaged to the cancellousbone 384 of the ulna 54 m. Construction in this manner is advantageousin that it permits the extent of the trauma experienced by the patientto be minimized. To further this goal, the distal end 386 of cageportion 80 m is shown to be generally cylindrically shaped so as tominimize the amount of bone that must be removed to prepare the ulna 54m for the second bearing component 18 m.

In FIGS. 16 through 18, a portion of a modular prosthetic joint kitconstructed in accordance with the teachings of a third aspect of thepresent teachings is generally indicated by reference numeral 10 n.Modular prosthetic joint kit 10 n is shown to include a bearing insert400, a retaining ring 402 and a second stem structure 14 n having anintegrally attached cage portion 80 n. Cage portion 80 n is shown toinclude a bearing aperture 406 for receiving bearing insert 400. In theparticular embodiment illustrated, cage portion 80 n also includes acircumferentially extending first ring groove 408 formed along theperimeter of bearing aperture 406 and operable for receiving a firstportion of retaining ring 402.

Bearing insert 400 is generally cylindrically shaped, having a pair ofspherical depressions 420 which collectively form a bearing surface thatis configured to mate with the spherically-shaped bearing portions 66 ofthe first bearing component 16. Bearing insert 400 also includes athrough hole 422 which is adapted to receive pin portion 62, preferablywithout transmitting load therebetween. A circumferentially extendingsecond ring groove 424 is formed in the outer perimeter of bearinginsert 400, the second ring groove 424 being operable for receiving asecond portion of retaining ring 402. Construction in this manner isadvantageous in that the surgeon may select a bearing insert 400 from aplurality of bearing inserts 400 to adapt prosthetic joint 10 n to thepatient.

In the particular embodiment illustrated, bearing aperture 406 is shownto include a plurality of radially outwardly extending tab apertures 430and bearing insert 400 is shown to include a plurality of radiallyoutwardly extending tabs 432. If desired, a first one of the tabapertures 430 and a first one of the tabs 432 may be sized differentlythan the remaining tab apertures 430 and tabs 432, respectively, to keythe bearing insert 400 to a specific orientation relative to second stemstructure 14 n.

With specific reference to FIG. 18, each of the pair of sphericaldepressions 420 includes a first spherical portion 450 and a secondspherical portion 454. Each of the first spherical portions 450 areformed into bearing insert 400 along an axis 456 that is coincident withthe longitudinal centerline of the bearing insert 400. Each of the firstspherical portions 450 are formed by a spherical radius approximatelyequal in magnitude to the spherical radius which defines thespherically-shaped bearing portion 66 of each of the condyle portions 60of first bearing component 16. The distance between the spherical radiialong axis 456 is equal to a predetermined distance, d.

The centerpoint 456 of the spherical radius that defines one of thefirst spherical portions 450 is employed to generate the secondspherical portion 454 on the opposite face of the bearing surface. Asecond centerline 468 is constructed from centerpoint 460 toward theopposite face at a predetermined constraint angle 470, such as 3.5degrees. The spherical radius that defines the second spherical portion454 on the opposite face is generated from a second centerpoint 472which is positioned along the second centerline 468 at a distance d fromcenterpoint 460. Construction of bearing insert 400 in this mannerpermits first bearing component 16 to rotate about centerline 456, aswell as to pivot relative to bearing insert 400 about thespherically-shaped bearing portion 66 of each of the condyle portions60.

A transition zone 480 is formed between each of the first and secondspherical portions 450 and 454 wherein a radius is formed at theintersection of the radii which define the first and second sphericalportions 450 and 454 to “soften” the transition between the first andsecond spherical portions 450 and 454 to render the movement of thecondyle portions 60 over the first and second spherical portions 450 and454 more comfortable to the patient.

Those skilled in the art will understand that the degree of theconstraint may be defined by the constraint angle. Accordingly, modularprosthetic joint kit 10 n preferably includes a plurality of bearinginserts 400, each having a bearing surface with a second sphericalportion 454 that is defined by a different constraint angle. Thoseskilled in the art will also understand that the degree of theconstraint may be additionally or alternatively defined by a constraintcharacteristic, which is illustrated in FIGS. 19A through 19D.

In FIG. 19A, bearing insert 400 a has a first predetermined constraintcharacteristic orientation wherein the centerlines which define theradii which define first and second spherical portions 450 and 454 arecontained in a plane which is generally perpendicular to thelongitudinal axis of the ulna. Construction of bearing insert 400 a inthis manner provides a varying degree of axial constraint. In FIG. 19B,bearing insert 400 b has a second predetermined constraintcharacteristic wherein the centerlines which define the radii whichdefine first and second spherical portions 450 and 454 are contained ina plane which is at approximately 45° to the longitudinal axis of theulna. Construction of bearing insert 400 b in this manner provides avarying degree of a combination of axial and varus/valgus constraint. InFIG. 19C, bearing insert 400 c has a third predetermined constraintcharacteristic wherein the centerlines which define the radii whichdefine first and second spherical portions 450 and 454 are contained ina plane which is generally parallel the longitudinal axis of the ulna.Construction of bearing insert 400 c in this manner provides a varyingdegree of varus/valgus constraint. In FIG. 19D, bearing insert 400 d isconstructed in a manner that is generally similar to that of bearinginserts 400 a, 400 b and 400 c except that the constraint angle employedto construct bearing insert 400 d is rotated form point x1 to y1 asindicated in FIG. 19 d. As a result, there is no single line oforientation in which the constraint is limited. Construction of bearinginsert 400 d in this manner provides a varying degree of constraint inboth an axial direction and a varus/valgus direction.

In FIGS. 20A through 22, a portion of a modular prosthetic joint kitconstructed in accordance with the teachings of an alternate embodimentof the third aspect of the present teachings is generally indicated byreference numeral 10 p. Modular prosthetic joint kit 10 p is similar tomodular prosthetic joint kit 10 n in that it includes a bearing insert400 p and a second stem structure 14 p having a integrally attached cageportion 80 p.

Cage portion 80 p is shown to include a bearing aperture 406 p forreceiving bearing insert 400 p. In the particular embodimentillustrated, cage portion 80 p includes a plurality of tab apertures 430p, a plurality of tab slots 500 and a hook structure 502. Each of thetab apertures 430 p extends axially through cage portion 80 p andcircumferentially around a portion of bearing aperture 406 p. Each ofthe tab slots 500 intersects one of the tab apertures 430 p and extendscircumferentially around a portion of bearing aperture 406 p away fromits associated tab aperture 430 p. Hook structure 502 is adjacent one ofthe tab apertures 430 p and extends radially inwardly andcircumferentially around a portion of bearing aperture 406 p. A clipslot 510 is formed circumferentially through hook structure 502.

Bearing insert 400 p is generally similar to bearing insert 400 exceptfor the configuration of the plurality of tabs 432 p and theincorporation of a clip structure 520 into a bearing body 522. Each ofthe plurality of tabs 432 p is relatively thin and do not extend axiallyacross bearing insert 400 p. This permits the tabs 432 p of bearinginsert 400 p to be aligned to a tab aperture 430 p and bearing insert400 p to be rotated so that each of the tabs 432 p is disposed withinone of the tab slots 500 to thereby prevent bearing insert 400 p frommoving in an axial direction.

Clip structure 520 is preferably a metal or plastic fabrication which issuitable for molding into bearing body 522. Clip structure 520 includesan arm structure 530 which extends from a clip body 532 and terminatesat its distal end at a hook member 534. Clip structure 520 is configuredand incorporated into bearing body 522 such when bearing insert 400 p isrotated to engage tabs 432 p into tab slots 500, arm structure 530simultaneously engages clip slot 510 in hook structure 502. Rotation ofbearing insert 400 p to a predetermined rotational position relative tohook structure 502 permits hook member 534 to engage an edge 540 of hookstructure 502. Arm structure 530 resiliently biases hook member 534against edge 540, thereby inhibiting rotation of bearing insert 400 pwhich would cause tabs 432 p to disengage tab slots 500.

In FIG. 20B, bearing insert 400 p′ is illustrated to be configuredsimilarly to bearing insert 400 p except that a locking aperture 800 isformed into one of the tabs 432 p′. Bearing insert 400 p′ is insertedinto bearing aperture 406 p′ aligned such that each of the tabs 432 p′is aligned to an associated one of the tab apertures 430 p′. Bearinginsert 400 p′ is then rotated so that each of the tabs 500′ is disposedwithin one of the tab slots 440 p′ and locking aperture 800 is alignedto a corresponding locking aperture 802 formed in the integrallyattached cage portion 80 p′ of second stem structure 14 p′. Engagementof tabs 500′ into their respective tab slots 440 p′ prevents bearinginsert 400 p′ from moving in an axial direction. Alignment of lockingapertures 800 and 802 to one another permits a pin 806 to be insertedtherethrough to prevent bearing insert 400 p′ from rotating relative tointegrally attached cage portion 80 p′. In the particular embodimentillustrated, pin 806 includes a head portion 808, a body portion 810 andan end portion 812. Head portion 808 has a diameter which is larger thanthe diameter of the hole formed by locking apertures 800 and 802. Bodyportion 810 is preferably smaller in diameter than the diameter of thehole formed by locking apertures 800 and 802.

A plurality of slots 814 are formed in end portion 812 which creates aplurality of fingers 816 which are flexible relative to the longitudinalaxis of pin 806. Fingers 816 flex inwardly toward the longitudinal axisof pin 806 when pin 806 is inserted to locking apertures 800 and 802,eliminating the interference therebetween to permit the fingers 816 ofend portion 812 to pass through integrally attached cage portion 80 p′and bearing insert 400 p′. Once the fingers 816 have passed throughintegrally attached cage portion 80 p′ and bearing insert 400 p′, theyflex outwardly away from the longitudinal axis of pin 806 to inhibit theunintended withdrawal of pin 806 from locking apertures 800 and 802.Intended withdrawal of pin 806 from locking apertures 800 and 802 may beeffected through the flexing of fingers 816 inwardly toward thelongitudinal axis of pin 806.

Those skilled in the art will understand, however, that the pin 806 forlinking first and second stem structures 12 and 14 p′ may be constructeddifferently. As shown in FIG. 20C, for example, the pin 806′ includeshead and end portions 808′ and 812′ having chamfered abutting surfaces808 p′ and 812 p′, respectively. The chamfered abutting surfaces 808 p′and 812 p′ can abut the locking apertures 800 and 802, similar to thepin 806. As illustrated, the pin 806 in FIG. 20B includes the headportion 808 that is larger than the locking apertures 800 and 802 andthe end portion 812 that can flex so that it can be smaller than thelocking apertures 800 and 802 to allow passage of at least a portion ofthe pin 806 through the locking apertures 800, 802. One skilled in theart will understand that a locking pin can generally pass through anaperture and be held therein, through some mechanism, to allow forinterconnection or locking of the various portions relative to oneanother. Nevertheless, the chamfered abutting surfaces 800 p′ and 812 p′can allow for a selected engagement of a pin 806′ between the lockingapertures 800, 802. Additionally, the end portion 812′ includes achamfered lead portion 812 p″. The chamfered lead portion 812 p″ canassist in allowing the pin 806′ to be passed through the lockingapertures 800, 802. Although it will be understood that the end portion808′ can be larger than the locking apertures 800, 802 so that the pincan only pass a selected distance through the locking apertures and beheld relative to the cage portion 80 p′ and the bearing insert 400 p′.As discussed above, in relation to the locking pin 806, the leading end812 can be allowed to pass through the locking apertures 800, 802,allowing the legs 816 to flex such that the head 812 passes through thelocking apertures 800, 802, similar to the head portion 812′ which isconfigured with the chamfered lead portion 812 p″ to allow for the pin806 to pass through the locking aperture 800, 802. However, the endportion 808′ is sized to not pass through the locking aperture 800, 802so that the pin 806′ can be held in a selected location. Pin 806′ isinstalled by simply pressing it through the bearing insert 400 p′.

In FIGS. 23 and 24, a portion of a modular prosthetic joint kitconstructed in accordance with the teachings of a fourth aspect of thepresent teachings is generally indicated by reference numeral 10 q.Prosthetic joint kit 10 q is shown to include first stem structure 12,second stem structure 14, first bearing component 16 and second bearingcomponent 18 q. Second bearing component 18 q is substantially similarto second bearing component 18 except that cage portion 80 q is shown toinclude a cam structure 600. Cam structure 600 includes a lobe member602 that extends radially outwardly and terminates at a tip 604. Lobemember 602 is configured such that tip 604 contacts the base 102 ofU-shaped member 40 to inhibit further relative rotation between firstand second stem structures 12 and 14 when the first and second stemstructures 12 and 14 are placed in a position corresponding to themaximum extension of a patient's arm. Configuration of second bearingcomponent 18 q in this manner is advantageous in that it limits theamount by which a patient may rotate their ulna relative to theirhumerus to prevent hyperextension of the joint.

In FIGS. 25 and 26, a portion of a modular prosthetic joint kitconstructed in accordance with the teachings of a fifth aspect of thepresent teachings is generally indicated by reference numeral 700.Prosthetic joint kit 700 is shown to include a first stem structure 702and a second stem structure 704. First stem structure 702 includes astem member 710, the distal end of which is configured to fit within themedullary canal of an ulna. A first bearing 712 and a coupling structure714 are incorporated into the proximal end of first stem structure 702.First bearing structure 712 is generally spherically shaped. Couplingstructure 714 includes a link member 720 and a retainer member 722. Linkmember 720 is fixedly coupled to first bearing 712 at a first end and toretaining structure 722 at a second end with link member 720 extendingtherebetween along an axis generally coincident the longitudinal axis offirst stem structure 702. Retaining structure 722 is illustrated to bespherically shaped with flattened ends.

Second stem structure 704 is shown to include a stem member 730 with aproximal end that is configured to fit within the medullary canal of ahumerus. A second bearing structure 732 is incorporated into the distalend of second stem structure 704. Second bearing structure 732 includesa generally spherical second bearing surface 740 and a T-shaped couplingaperture 742. A first portion 744 of coupling aperture 742 has a widthwhich is larger than the width of retaining structure 722. First portion744 is oriented at a position of maximum flexion. In the particularembodiment illustrated, the position of maximum flexion is illustratedto be about 90° to the longitudinal axis of second stem structure 704.However, those skilled in the art will understand that the position ofmaximum flexion may be tailored in a desired manner and may range ashigh to an angle of approximately 135° to 150° to the longitudinal axisof second stem structure 704, depending on the particular application. Asecond portion 746 of coupling aperture 742 has a width which isslightly larger than that of link member 720. Second portion 746 extendscircumferentially around a portion of second bearing surface 740 in aplane that coincides with the longitudinal axis of second stem structure704. The first and second portions 744 and 746 of coupling aperture 742intersect and terminate at spherically shaped cavity 750.

To use prosthetic joint kit 700, first and second stem structures 702and 704 are inserted into the medullary canals of the ulna and humerus,respectively. First stem structure 702 is then positioned proximate thefirst portion 744 of coupling aperture 742 and retaining structure 722is inserted through first portion 744 and into spherically shaped cavity750. At this point, first and second bearing surfaces 712 and 740 are incontact with one another and transmit load therebetween rather thanthrough coupling structure 714. Coupling of first and second stemstructures 702 and 704 is complete when first stem structure 702 isrotated into second portion 746. In this position, first and second stemstructures 702 and 704 are linked or constrained since the width ofretaining portion 722 is larger than the width of second portion 746 andthereby prevents the withdrawal of first stem structure 702 fromcoupling aperture 742.

While the prosthetic joint devices 10 and 10 a have been illustrated ashaving modular flanges 20 that are fixedly but removably coupled to thefirst stem structure 12, those skilled in the art will understand thatthe teachings, in its broader aspects, may be constructed somewhatdifferently. For example, the stem structure and modular flange may beunitarily formed as shown in FIG. 27. In this embodiment, the stem 12 pis illustrated to be similar to the stem 12, but includes a flangestructure 92 p having a flange member 96 p and a coupling portion 96 p′that couples the flange member 96 p to the distal portion 32 p of thestem 12 p. The flange member 96 p is generally parallel the stem member30 p and is employed to compress a bone graft against the stem member 30p. Unlike the modular flange 20 that was described in detail, above, theflange structure 92 p must be fitted over a bone graft 110 or the bonegraft must be placed into the aperture 800 between the stem member 30 p.

Another example of an integrally formed (i.e., non-removable) flangestructure is illustrated in FIGS. 28 and 29. In this example, the stem12 q is illustrated to be similar to the stem 12 p in that it includes aflange structure 92 q having a flange member 96 q and a coupling portion96 q′ that couples the flange member 96 q to the distal portion 32 q ofthe stem 12 q. The flange member 96 q, however, is arcuately shaped andincludes a contact tab 804. The flange structure 92 q is formed with apredetermined degree of resiliency, which may result from thecharacteristics of the material from which the flange structure 92 q isformed or by controlling the geometry (i.e., cross-sectional shape andarea) of the flange structure 92 q. The resiliency of the flangestructure 92 q permits the flange member 96 q to act as a leaf springthat biases the contact tab 804 toward the stem member 30 q.Accordingly, the flange may be employed to apply compression to the bonegraft 110 q without fasteners or other securing means. As illustrated inFIG. 30, those skilled in the art will readily understand, however, thata predetermined amount of resiliency may also be incorporated into aflange structure 92 r that is fixedly but removably coupled to the stem12 r.

Those skilled in the art will also understand that although the modularflange 20 has been illustrated as being coupled to the stem 12 r via athreaded fastener 94 b, the teachings, in its broader aspects, may beconstructed somewhat differently. For example, cables 810 are employedto fixedly but removably retain the flange structure 92 s to the stem 12s as illustrated in FIGS. 31 and 32. The stem 12 s is generally similarto the stem 12, but includes a first coupling feature 812 instead of thebore 100. The flange structure 92 s includes a flange member 96 s and acoupling portion 96 s′. The coupling portion 96 s′ includes a secondcoupling feature 814 that is configured to cooperate with the firstcoupling feature 812 to locate the flange member 96 s relative to thedistal portion 32 s of the stem 12 s. In the example illustrated, thefirst coupling feature 812 is a generally trapezoidal dovetail member816 that extends outwardly from the distal portion 32 s of the stem 12 sand the second coupling feature 814 is a dovetail aperture 818 that isformed into the coupling portion 96 s′ and sized to engage the dovetailmember 816 in with a line-to-line fit (i.e., with very little or noclearance). The dovetail member 816 is preferably integrally formed ontothe stem 12 s but may alternatively be an independently formed componentthat is fixedly coupled to the distal portion 32 s via an appropriatecoupling means, such as threaded fasteners, press-fitting or shrinkfitting.

The flange member 96 s is shown to include a plurality of cross-holes820 that extend completely through the flange member 96 s in a directionthat is generally perpendicular the longitudinal axis of the flangemember 96 s. The cross-holes 820 are sized to receive the cable 810. Asthose skilled in the art will understand, the cables 810 are firstsecured around the humerus 38 s and the ends of the cables 810 areloosely secured via an appropriate coupling device, such as a cablesleeve 822. The cables 810 are then tensioned to urge the flange member96 s against the humerus 38 s and compress the bone graft 110 s by apredetermined amount. Thereafter, the coupling device is employed to fixthe ends of the cables relative to one another so as to maintain tensionin the cables 810.

While the first and second coupling features 812 and 814 have beenillustrated as being a dovetail member 816 and a dovetail aperture 818,respectively, those skilled in the art will appreciate that the firstand second coupling features 812 and 814 can be constructed somewhatdifferently. As illustrated in FIG. 33, for example, the first couplingfeature 812 t is illustrated as being a pair of pins 830 that arefixedly coupled to the distal portion 32 t of the stem 12 t and thesecond coupling feature 814 t is illustrated to be a corresponding pairof holes 832 that are formed into the coupling portion 96 t. The pins830 are preferably press-fit or shrunk fit into corresponding holes (notspecifically shown) that are formed into the distal portion 32 t of thestem 12 t but may be secured via other fastening means, such as welding,bonding, or threaded engagement where the pins 830 have a threadedportion that is threadably engaged to the holes in the distal portion 32t. Alternatively, the pins 830 may also be integrally formed as a partof the stem 12 t.

Another example is illustrated in FIGS. 34 and 35, where the firstcoupling feature 812 u is shown to include a mounting structure 840 withan arcuate mounting aperture 842 and the second coupling feature 814 uis shown to include an attachment hook 846. The mounting structure 840is coupled to the distal portion 32 u of the stem 12 u and extendsgenerally perpendicularly outwardly from the base 102 u of the U-shapedportion 40 u. The mounting aperture 842 is generally J-shaped andincludes a first portion 850, which is aligned generally perpendicularto the base 102 u, and an arcuate second portion 852, which extends awayfrom the stem member 34 u and the base 102 u. The attachment hook 846 isalso generally J-shaped, being configured to matingly engage themounting aperture 842. In this regard, the attachment hook 846 includesa leg portion 856 that extends downwardly from the flange member 96 uand an arcuate base member 858.

In coupling the first and second coupling features 812 u and 814 u,flange structure 92 u is initially positioned relative to the stem 12 usuch that the base member 858 is disposed within the first portion 850of the mounting aperture 842. The flange structure 92 u is then rotateddownwardly toward the stem member 34 u to permit the base member 858 toengage the second portion 852 of the mounting aperture 842. The cables810 are thereafter employed to fix the flange structure 92 u relative tothe stem 12 u.

With initial reference to FIG. 1 and further reference to FIG. 36, amodular joint prosthesis 1000 is illustrated. It will be understood thatthe illustrated modular prosthesis 1000 illustrated in FIG. 36 can besimilar to the prosthesis 10 illustrated in FIG. 1, though differencescan be provided and discussed herein. Nevertheless, like features andportions will be indicated with like reference numerals and notdescribed again in detail. Briefly, however, as discussed above, themodular prosthesis 1000 can be used as a linked elbow prosthesis,although it will be understood according to various embodiments that anunlinked or free elbow prosthesis can be provided, as discussed herein.The prosthesis 1000 can generally include the first stem structure 12,the second stem structure 14, a first bearing component 1002, the secondbearing component 18, and various other portions that can be provided orincluded in the modular prosthesis 1000 if selected. It will beunderstood that all or various portions are discussed above as includedin various embodiments. However, not each of the portions arenecessarily provided for each of the embodiments if so selected.

The first bearing component 1002 can define a first condyle portion 1004and a second condyle portion 1006. The condyle portions 1004, 1006, canbe similar to the condyle portions 60 illustrated and described above.According to various embodiments, each of the condyle portions 60 caninclude substantially similar spherical radii. Although the condyleportion 60 need not define a complete sphere, a portion of the sphere,which they can define, can include or define a spherical radius.According to various embodiments, however, the first condylar portion1004 can have a first spherical radius 1008 while the second condylarportion 1006 can include a second spherical radius 1010. The firstspherical radius 1008 can be different than the second spherical radius1010.

The spherical radii can be any appropriate dimension such as 1 mm toabout 3 cm, such as about 0.6 cm to about 2.0 cm. It will be understood,however, that the spherical radii 1008, 1010, can be any appropriatedimension. For example, the spherical radii 1008, 1010 can be selectedfor various purposes, such as to substantially mimic a specific anatomy,and as such the various ranges described herein are merely exemplary.Further, it will be understood that the dimensions 1008, 1010, which caninclude spherical radii, can be any appropriate dimensions. For example,it will be understood that the condylar portions 1004, 1006 need notspecifically define a portion of the sphere, a portion of a cylinder, orthe like. The condylar portions 1004, 1006 can be irregular such thatthey are not a regular shape or surface. The design of the condylarportions 1004, 1006 can be specific to various individuals andanatomies, thus not requiring a regular shape.

The condylar portions 1004, 1006 can include the various portions asdiscussed above. For example, the condylar portions 1004, 1006 candefine the bearing portion 66 which can be regular or irregular, asdiscussed above. Further, each can define the slotted apertures 68 orother appropriate connection portions, to interconnect with the distalportion 32, such as the legs 42 of the first end portion 12. It will beunderstood that the U-shaped portion 40, which includes the spaced apartthe legs 42, can also be referred to as a yoke or other appropriateportion. Further, each of the condyle portions 1004, 1006 can define thepin aperture 70 to interconnect with the condylar pin portion 62 tointerconnect the condylar portions 1004, 1006 in a selected manner. Asdiscussed above, however, the condylar portions 1004, 1006, can besubstantially formed as a single member or portion that can include thecondylar pin 62 a as a single portion with the condylar portions 1004,1006.

Further, as discussed above, the condylar portions 1004, 1006, thecondylar pins 62, and any other portions of the prosthesis 1000 can beformed of various materials. For example, it can be selected to form thecondylar portions 1004, 1006 from a single material, a compositematerial, or the like. For example, the condylar portions 1004, 1006 candefine the bearing surfaces 66 formed of a polymer material, such as ahigh molecular weight polyethylene. The second bearing member 18 canalso be made of similar materials. Nevertheless, they can also be formedwith a metal, metal alloy, ceramic, or the like to achieve variousresults.

Further, it will be understood that the second bearing portion 18 caninclude various features and be formed of various materials, includingthose discussed above. The second bearing member 18 can include thebearing cage 80, the second bearing cage 80 a which defines the slot150, or the substantially unconstrained or unlinked various embodimentsthat include the bearing member 82′ and the features thereof asdiscussed above. Therefore, it will be understood that the condylarportions 1004, 1006 can be interconnected with any appropriate secondbearing portion 18, 18′ including those described above.

Further, the prosthesis assembly 1000 can include various portions thatallow for the substantial non-linear alignment of the condylar portions1004, 1006 relative to one another. It can be selected to non-align oroffset a first center 1012 of the first condylar portion 1004 and asecond center 1014 of the second condylar portion 1006. It will beunderstood that the centers 1012, 1014, can be any operative center orportion of the prosthesis according to various embodiments and defininga geometrical center is merely exemplary. The centers can be offset invarious manners such as an anterior-posterior non-alignment, asuperior-inferior non-alignment, or combinations thereof.

For example, an anterior-posterior spacer kit can include a first spacer1016, a second spacer 1018, and a third spacer 1020. Each of the spacers1016-1020 can include a dimension 1016′-1020′ respectively. Thedimensions 1016′-1020′ can move or displace the selected condylarportions 1004, 1006 relative to the other. A selected spacer, such asthe spacer 1016, can be positioned in the slot 68 such that a passage1022 through the spacer 1016 aligns with the passage 72 through thecondylar portion 1006 so that when the leg 42 is positioned within theslot 68, the leg 42 is unaligned with the first condylar portion 1004. Asubstantially aligned axis 1024 can pass through the two centers 1012,1014 of the respective condylar portions 1004, 1006 and through thecondylar pin 62. Nevertheless, the spacer 1016 can offset a selectedcondylar portion, such as the second condylar portion 1006 relative tothe first condylar portion 1004. Therefore, an offset angle 1026 can beformed between the first condylar portion 1004 and the second condylarportion 1006.

In various configurations, such as an unaligned configuration, variousportions are optional. For example, the pin 62 is optional in variousconfigurations. As discussed above, the bearing members 1002 and 1006bear the force and the pin can assist with strength and stability of theassembly. Thus is the pin 62 can be omitted between the condyles.

The offset angle or distance 1026 can be any appropriate dimension. Theappropriate dimension can be selected for various purposes, such as thespecific anatomy of the patient, a selected result, or the like. Forexample, the offset angle can be about 1° to about 20°, such as about 3°to about 10°. Nevertheless, the offset angle can be any appropriateangle depending upon a selected condition. The offset angle 1026 can bealtered by choosing a different one of the spacers 1016-1020 and can beselected pre-operatively, intra-operatively, or at any appropriate time.

Each of the spacers 1016-1020 can include a passage or opening 1016a-1020 a. The opening can be a round bore, elongated, a slot or anyappropriate opening. The openings 1016 a-1020 a can be provided to alignor be oriented with the openings 72 in the first and second bearingmembers 1002 or 1006 and a selected passage 1016 a-1020 a.

The openings 72 can also be circular, oblong, slotted, or formed in anyappropriate shape or manner. The interaction of the opening 72 in thebearing members 1002 and 1006 and with the openings 1016 a-1020 a in thespacers 1016-1020 can help ensure an appropriate fit of the prosthesis1000.

A second set of spacers 1030-1034 can also be provided. The spacers1030-1034 can each include a dimension 1030′-1034′ respectively. Therespective dimension 1030′-1032′ can be any appropriate dimension andallow for a selected superior inferior offset. A selected spacer, suchas the spacer 1030, can be positioned in the slot 68 to offset thesecond condylar portion 1006 relative to the first condylar portion1004. The offset amount can be similar to the angle 1026 except in adifferent dimension or orientation. The spaces 1030-1034 can alsoinclude passages 1030 a-1034 a, respectively, that can be similar to thepassages 1016 a-1020 a. The passages 1030 a-1034 a can be round,slotted, oblong, etc. They can be provided to allow for a selectedorientation of the prosthesis 1000.

It will be understood, however, that any appropriate number of thevarious spacers such as the spacers 1016-1020 and the spacers 1030-1034can be provided for any appropriate purpose. For example, a plurality ofthe spacers 1016-1020 and 1030-1034 can be provided in minute anddiscreet differences to allow for an intra-operative selection of aselected offset or to allow for a plurality of offsets for creation froma set of instruments and portions.

With continuing reference to FIG. 36, a third set of spacers 1017, 1019,1021 can be provided. Although the discussion herein includes adiscussion related to three sets of spacers, it will be understood thata set of spacers can include any of the appropriate spacers, all of thespacers, or a selected portion thereof depending upon selected purposes.Nevertheless, the third set of spacers, called that for simplicity ofthe present discussion, can be formed dissimilar to the second set ofspacers 1030-1034. Nevertheless, the third set of spacers 1017-1021 caninclude a first side 1017 a-1021 a that has a dimension that is the sameor different than a second side 1017 b-1021 b. The various sides caninclude any appropriate dimension, however, the dimension of side 1017b-1021 b can be varied for various purposes, such as a reason similar tovarying the dimension of the first spacer sets 1016-1020. The side 1017b-1021 b can include a dimension 1017′-1021′ that can be selected forany appropriate purpose, such as a selected offset, including ananterior or posterior offset. The offsets can be any appropriateoffsets, and can be similar to, different, or complementary to theoffsets of the spacers 1016-1020. Further, the third set of spacers1017-1021 can include a third side 1017 c-1021 c. It will be understoodthat the various sides can be any appropriate portions of the spacers1017-1021 and has described the sides merely for the discussion herein.Nevertheless, the third side, 1017 c-1021 c can also include a variabledimension 1017″-1021″. The dimension 1017″-1021″ can include anyappropriate dimension, such as dimensions similar to the dimensions ofthe second spacer sets 1030-1034.

Therefore the third spacer set 1017-1021 can include a variabledimension of more than one side or portion of the spacers 1017-1021 forvarious purposes. For example, it can be selected to provide the spacers1017-1021 to include a selected offset in more than one direction ororientation relative to the prosthesis 1000 or an anatomy into which itis positioned. Therefore, the spacers 1017-1021 can be used to achievean appropriate orientation of the prosthesis 1000 in a single member.Nevertheless, it will be understood that a modular spacer assembly canbe provided to achieve a selected offset in the prosthesis 1000. Havinga spacer member that is formed as a single portion or body is notnecessary and a modular spacer system can be provided. Nevertheless, asingle spacer can include an offset in various dimensions, as exemplaryillustrated in the spacers 1017-1021.

Further, the spacers 1017-1021 can include a passage 1017 d-1021 dsimilar to the passages described above in the various spacer systems.The passage 1017 d-1021 d can be circular, oblong, slotted, or anyappropriate orientation, size, or the like. The select passage 1017d-1021 d can be provided to interact with the passages 72 and thebearing members 1002 and 1006 to achieve a selected orientation of thespacer members relative to the bearing members 1002 1006.

With reference to FIG. 37 and continuing reference to FIG. 36, thedetailed cross-sectional view of the condylar portions 1004, 1006relative to the second bearing member 18 is illustrated in an assembledmanner. As illustrated in FIG. 37, a selected one of the spacers, suchas the spacer 1030 can be inserted into the slot 68 to displace thesecond condylar portion 1006 relative to the first condylar portion1004. Therefore, the angle 1026 is formed between the first center 1012and the second center 1014 with the condylar portions 1004, 1006.Further, as illustrated in FIG. 37, the second condylar portion 1006 caninclude the dimension 1010 that is larger than the dimension 1008 of thefirst condylar portion 1004. Thus, the condylar portion 1006 can bedesigned to mimic a selected portion of the anatomy, if so selected.

Nevertheless, it is still understood that the bearing surfaces 66 canbear on the bearing member 84 of the second bearing member 18 in anappropriate manner. Thus, the condylar pin 62 does not or is notrequired for proper articulation and may not engage a selected portionof the bearing member 84 after positioning or implantation of theprosthesis 1000. For similar reasons, the pin 62 is not required in theassembly as discussed above. The pin 62 can be omitted for variousreasons, such as ease of assembly. Although one skilled in the art willunderstand that the pin 62 can be used for various reasons, includingstability, strength, alignment, and the like. Also, the selectedanatomical geometry can be obtained with the prosthesis 1000, which canuse any or a plurality of the spacers 1016-1020, 1030-1034, or 1017-1021to achieve any appropriate offset or angle and also the dimension of thecondylar portions 1004, 1006 can be selected to achieve the appropriateresults.

With reference to FIG. 38, a modular prosthesis assembly 1060 caninclude various portions, including those discussed above. It will beunderstood that the similar portions can be referenced by like numeralsand a detailed description thereof need not be necessary here tounderstand the various embodiments. Nevertheless, the first stemassembly 12 can be provided to interconnect with a first bearingassembly 1062 and a second stem assembly 14 and a third stem assembly220. As discussed above, the fourth bearing component 222 can beprovided with the stem assembly 220 to interconnect with the radius toreplace articulating portion thereof. It will be understood that thestem assembly 220 can be provided with various portions to achieve areplacement of a selected portion of the radius.

It will be further understood that, as described above in variousembodiments, that the bearing portion 222 can be formed as a singlemember with the second stem assembly 14 according to variousembodiments. The first bearing assembly 1062 can include a firstcondylar portion 1064, a second condylar portion 1066 and the extension240. The extension 240 can be provided to extend from a selected portionof the first bearing member 1062 such as medial or laterally from thefirst bearing member 1062. The extension 240 can define the extensionbearing member 242 that can articulate with the bearing portion 222 ofthe stem 220 or with the natural portion of the radius. Further, asdiscussed above, the bearing surface 222 can articulate with the naturalportion of the humerus if so selected. Also, the second bearing member18 can be provided in a substantially linked, unlinked or unconstrained,semi-constrained or linked, or a slot that allows access to the bore 86in any appropriate manner.

The first bearing member 1062 can be interconnected with the first stemmember 12 in any appropriate manner, including the various screws orfixing member 64 as described above. Further, the condylar portions1064, 1066 can be interconnected with the condylar pin 62 c in anyappropriate manner, including those discussed above. Nevertheless, thefirst condylar member 1064 can be provided in a different manner,geometry, size, etc., than a second condylar member 1066.

As discussed above, the first condylar member 1064 can have acenterpoint 1068 that can define a center of a sphere or any otherregular or irregular shape. For example, the first condylar portion 1064can define a spherical radius 1070 that extends from the center 1068 toan edge of the condylar member 1064. The second condylar member 1066 canalso define a center 1072, which can be the center of a sphere or anyother appropriate shape or irregular shape. Further, the second condylarportion can define a second spherical radius 1074. As discussed above,the spherical radii 1070, 1074 can be provided to be equal, different,or in any appropriate combination. Nevertheless, it will be understoodthat the condylar portions 1064, 1066 can include a different dimensionand be interconnected with the various portions, such as the extension242 to articulate with various portions of the anatomy or prosthesespositioned therein. It will also be understood that the condylarportions 1064, 1066 can interconnect with the first stem member 12 inany appropriate manner. Therefore, various further portions, such as thespacers 1016-1020, 1030-1034, or 1017-2021 can be provided with theprosthesis system 1060.

It will be understood that the various embodiments of the prostheses,whether linked or unlinked or constrained or unconstrained can beprovided in various portions of the anatomy. Nevertheless, the exemplaryelbow prostheses can be provided in various manners for selection by auser. As discussed above, a kit can include each and every of thevarious portions of the various embodiments for selection by a userduring an operative procedure, prior to an operative procedure, or atany appropriate time. Therefore, the modular prosthesis, according tovarious embodiments, can be provided for use by a user in a selectedmanner to achieve a selected result.

Further, with exemplary reference to FIG. 39, the prosthesis 1000 can bepositioned in the anatomy in any appropriate manner. The modularprosthesis can be provided to be positioned relative to various portionsof the anatomy, such as a humerus, a radius, an ulna, or any appropriateportions through a selected incision 1200 relative to the elbow 1202joint between the hummers 1204 and ulna 1206. It will be understood thatthe modular nature of the prosthesis 1000, can be provided for aprocedure that can be performed through a relatively minor incision thatneed not be larger than various portions of the modular prosthesis. Thiscan achieve various results, such as minimizing recovery time,minimizing operation time, or various selected results. Further, asdiscussed above, the modular nature of the various portions and variousembodiments can provide for achieving a selected revision procedure. Forexample, having the various sizes of the condylar portions, which caninclude different dimensions, a revision procedure can be provided tomaintain or augment a selected result to achieve a more anatomicalresult in a selected period. Further, the prosthesis, according tovarious embodiments, can be changed from a constrained to unconstrainedor from an unconstrained to a constrained. The change can be providedduring a selected procedure, such as a revision procedure to account forchanges in the anatomy over time. Nevertheless, the modular prosthesisaccording to various embodiments can be provided for selection by a userto achieve a more natural anatomical result after implantation of theprosthesis.

With reference to FIG. 40, a humeral prosthesis stem assembly orstructure 1300 is illustrated. The stem assembly 1300 can include afirst and second arm 1302, 1304 to cooperate or engage the pair ofcondyle portions 60, according to various embodiments. The stem assembly1300 can include a stem portion 1306 that is operable to extend into acanal, such as the intramedullary canal of a humorous. Extending withthe humeral stem assembly 1300 can be a flange attachment or connectionmember 1310. The flange attachment member 1310 can define a dovetail,such as a male dovetail 1312. The flange attachment member 1310 includesa bore or passage 1314.

A modular flange member 1320 can interconnect with the flange attachmentmember 1310. The modular flange member 1320 can define a female dovetailconnection 1322. The modular flange member 1320 can also include apassage or bore 1324 through which a locking screw or set screw 1326 canpass. During or with an implantation procedure, the modular flangemember 1320 can slide over the flange attachment member 1310 and the setscrew 1326 can lock the modular flange member 1320 to the flangeattachment member 1310.

It will be understood, according to various embodiments, that themodular flange member 1320 includes a female or male connection portionother than the dovetail female dovetail connection 1322. The flangeattachment member 1310, however, can include any appropriate connectionportion other than the male dovetail 1312. The appropriate connectionportion allows the flange member 1320 to be slid axially over the flangeattachment member 1310. By axially sliding or moving the flange memberto connect it to the flange attachment member 1310 increased resistanceto rotation or torsion can be achieved of the flange member relative tothe remainder of the stem assembly 1300. As discussed above, the flangemember 1320 can be provided to resist rotation of the stem assembly 1300in the anatomy.

For example, the male and female dovetails can be reversed or otherappropriate configurations can be provided. For example, a maleT-portion and a female T-portion can be provided on the respectiveflange attachment member 1310 and modular flange members 1320. TheT-portions can also allow an appropriate cooperation of the flangemember 1320 and the flange attachment member 1310.

The flange member 1320 can be provided with any appropriate length1320L. The length 1320L can also be provided to vary amongst a pluralityof the flange members 1320. The plurality of the flange members 1320 canbe provided in a kit, such as in the prosthesis assembly 1000illustrated in FIG. 36 or any other appropriate kit or modularprosthesis assembly.

As discussed above, the flange member 1320 or the flange attachmentmember 1310 can be provided to engage the humerus to assist in reducingor eliminating rotation of the humeral assembly 1300 after or duringimplantation. The modular flange member 1320 that can be provided in aplurality of lengths and the appropriate length can be selected by auser, such as the surgeon, during a procedure. The length of the modularflange member 1320 can be selected based upon the length of thepatient's humerus, the amount of area to be covered to resist rotation,and for other selected purposes.

The modular flange member 1320 can also be interconnected with theflange attachment member 1310 at any appropriate time. For example, theflange member 1320 can be interconnected with the flange attachmentmember 1310 prior to positioning the humeral stem assembly 1300 into ahumerus of the patient. Alternatively, the flange member 1320 can beinterconnected with the flange attachment member 1310 after positioningthe stem portion 1306 within the humerus.

According to various embodiments, a multiple or plural flange humeralassembly 1330 can be provided, as illustrated in FIG. 41. The humeralassembly 1330 can include two arms or furcations 1332 and 1334 to engagethe condyle bearings, as discussed above. The humeral assembly 1330 canfurther include a stem portion 1336 to engage or be positioned in thehumerus, as also discussed above. A modular flange assembly 1340 withmultiple members are assembled to engage the stem portion 1336 cooperatewith the stem portion 1336. The modular flange assembly 1340 can includeany appropriate number of modular members, including two as discussedherein. Also, the modular flange assembly can connect directly to thestem portion 1306 or any appropriate portion of the humeral assembly1330, including near the two arms or furcations 1332, 1334. The modularflange assembly 1340 can allow for greater flexibility during aprocedure and multiple sets of the modular flange assembly 1340 canfurther increase flexibility.

A flange connection member 1342 can include a connection portion 1344 toconnect with an arcuate mounting aperture 842. The arcuate mountingaperture 842 can be provided to interconnect with the connection portion1344 as discussed above. The arcuate connection aperture 842 and theconnection portion 1344 can allow for a selected connection of theflange connection member 1342 to the remainder of the humeral assembly1330.

In addition, the flange connection member 1342 can include a threadedbore or passage 1346 similar to the passage 1314 discussed in FIG. 40.In addition, the flange connection member 1342 includes a male dovetailconnection portion 1348. A separate modular flange member 1352 includesa length 1352L. The modular flange member 1352 includes a femaledovetail connection region 1354 to cooperate with the male dovetail1348. As discussed above, however, a dovetail connection is not requiredand any appropriate selectable connection can be provided.

A passage 1356 if formed through the flange member 1352. A locking orset screw 1358 can pass through the passage 1356 and the passage 1346 toassist in locking or holding the flange member 1352 to the flangeconnection member 1342. The flange member 1352 can be held or fixedrelative to the flange connection member 1342 with any appropriatemechanism, such as a tab or deflectable finger.

As discussed above, the flange member 1352 can be provided in anyappropriate length. Further, the length 1352L can vary among a pluralityof the flange members 1352. A plurality of the flange members 1352 canbe provided in a kit or in a modular assembly system, such as themodular assembly system 1000. The user can select the appropriate lengthflange member 1352 for any appropriate reason, such as that discussedabove.

In addition, the kit, or any appropriate kit, can include a humeralassembly portion, such as the humeral assembly 1300 or the humeralassembly 1330. A selection of an appropriate humeral assembly can bemade for appropriate purposes, such as providing for a selected orunique anatomy of a patient. For example, if a patient's anatomy issubstantially planar the flange attachment member 1310 can be used.

If varying widths of a patient's anatomy need to be accommodated thenthe multiple modular flange assembly 1340 can be used to accommodate thevarying widths with a plurality of members. For example, the arcuateconnection 1344 can position the flange connection member 1342 at anyselected distance from the stem portion 1336. The flange member 1352 canthen be selectively interconnected with the flange connection member1342 during an implantation procedure.

It will be understood that the flange assembly 1340, the flange member1320, or a flange according to the various embodiments can be providedwith any appropriate humeral assembly. The humeral assembly can beimplanted for forming a portion of an elbow joint, as discussed above.The flange assembly can be provided with a modular member to select aselected length, offset, or other configuration of the flange memberrelative to the stem portion of the humeral assembly.

As discussed above, a prosthetic joint 10 can include a bearingcomponent 16 that includes first and second condyle portions 60. Asfurther discussed above, and illustrated in FIG. 1, the condyle portionscan be connected to the first stem structure 12 with a fastener 64. Thefastener 64 can pass through bores or passages in the condyle portions60 and in the stem structure 12 to connect the condyle portions 60 tothe stem structure 12. According to various embodiments, as illustratedin FIGS. 42-44, a first and second stem structures 12, 14 and thebearing component 16 can be associated to form an elbow jointprosthesis.

For example, a fastener 64′ can be provided and positioned tointerconnect the condyle portions 60 with the arms or furcations 42. Thefastener 64 can extend through the furcation 42 and engage the condyleportion 60 to hold the condyle portion relative to the respectivefurcation 42. Similarly, the fastener 64′ can pass through or engageboth the condyle portion 60 and the respective furcation 42 to hold thecondyle portion 60 relative to the respective furcation 42. The fastener64′ can include a first and a second fixation or fastening region. Asdiscussed herein, first and second fastening regions can include firstand second fastener grooves 1370, 1372 and a fastener thread 1374.

The fastener 64′ includes a head 1364, a shaft 1366 extending from thehead, and a distal tip or region 1368. The fastener 64′ further includesa first fastener groove 1370 and a second fastener groove 1372. Theshaft 1366 includes a male fastener thread 1374 located intermediate thehead 1364 and the distal tip 1368 in the depicted embodiment. Thefastener thread 1374 can be provided to engage a female thread, such asa female thread 1376 of the threaded fastener aperture 44. The fastener64′ also passes through at least one part of the mounting aperture 72 inthe condyle portion 60.

During an assembly, the fastener 64′ can pass through a first part ofthe mounting aperture 72, pass through the threaded fastener aperture44, and pass through a second part of the mounting aperture 72. It willbe understood that the fastener 64′ need only pass through a one part ofthe mounting aperture 72. The fastener 64′ can be held at a selectedlocation relative to the furcation 42 and the condyle portion 60 atleast with the fastener threads 1374 in the threaded fastener aperture44.

The threaded interaction between the fastener threads 1374 and thefemale threads 1376 can create or generate a first fasteninginteraction. A second fastening interaction can be formed with a secondfastener and by either or both of the grooves 1370 and 1372 in thefastener 64′ and cooperating grooves 1380 and 1382 included in themounting aperture 72. A groove can also be defined in the threadedfastener aperture 42. The second fastener can be at least one of a firstlocking spring 1386 and a second locking spring 1388. The springs 1386,1388 can be any appropriate springs, such as helical spring or flexspring members. The second fastener can also be a locking ring or C-ring1390. The second fastener is provided to cooperate with one of theselected groove pairs 1370 and 1380 or 1372 and 1382. The lockingsprings 1386, 1388 can be positioned between the pairs of grooves 1370,1380 or 1372, 1382 to resist movement of the fastener 64′ within any ofthe threaded fastener aperture 44 or mounting aperture 72.

As best illustrated in FIG. 44, the fastener 64′ can be positionedwithin the respective apertures 72, 44, and the springs 1386, 1388 canbe positioned within the groove pairs 1370, 1380 or 1372, 1382 to assistin holding the fasteners 64′ within the apertures. At least one of thesprings 1386, 1388 is placed in the grooves 1380, 1382 of the condyleportions 60 or any appropriate portion of the assembly during assembly.The fastener 64′ is inserted to engage at least one of the springs 1386,1388 which flexes the spring 1386, 1388. The fastener 64′ is thenfurther inserted to allow the spring 1386, 1388 to relax into therespective fastener groove 1370, 1372

The second fastener is provided to assist in resisting movement of thefastener 64′. For example, once the fastener 64′ is positioned in theprosthesis 10 and multiple articulations or cycles of the prosthesis 10occurs within a patient, the fastener 64′ may loosen relative to thefurcation 42. The locking spring 1386, 1388 or any appropriate lockingmember can ensure that the fastener 64′ does not move more than aselected distance. Accordingly, the condyle member 60 can be maintainedconnected to the respective furcations 42.

The first bearing component 16, according to various embodiments, can beheld in place relative to the first stem structure 12, as discussedabove. It can be selected to provide both a first and second interactionfor the fastener 64′. The first bearing component 16 can then beimplanted or positioned to articulate with the second bearing component18.

With reference to FIGS. 45-47B, a second stem structure 1400 having asecond bearing component 1402 can include a cage or enclosed structure1403 that can couple with or hold a bearing member 1404 in a selectedposition in a second stem structure 1400. The bearing member 1404 candefine a bearing surface 1406 that can include two faces or opposingpartially- or semi-spherical bearing surfaces. A through bore or passage1407 can also be defined through the bearing member 1404. The bearingsurfaces 1406 and passage 1407 can have any appropriate configuration,including that discussed above. For example, the bearing surface 1406can include two bearing sections defined around axes that are at anangle relative to one another. The various configurations of the bearingstructure of the bearing member 1404 are discussed above and notrepeated here.

The bearing member 1404 can be held within the cage 1403 with a holdingmember, such as tabs 1410 a-1410 c included in an exterior surface 1411of the bearing member 1404. The holding member can include portions ofboth the bearing member 1404, the cage 1403, or other members, asdiscussed herein. The tabs 1410 a-1410 c can extend a height 1412 abovethe exterior surface 1411 of the bearing member 1404. The tabs 1410a-1410 c can pass through tab entries 1420 a-1420 c in the cage 1403formed in a sidewall 1422 of the cage 1403. Although three tabs 1410a-1410 c are discussed and illustrated here, any appropriate number oftabs can be provided.

Grooves or depressions 1426 a-1426 c are defined within an interiorsurface or below an interior surface 1428 of the cage 1403. The groove1426 a-1426 c can engage or cooperate with the tabs 1410 a-1410 c, asillustrated in FIG. 47A. The tabs 1410 a-1410 c can be made to engage orcooperate with the grooves 1426 a-1426 c by moving the bearing member1404 into the cage 1403 by positioning or aligning the tabs 1410 a withthe tab entries 1420 a-1420 c. The bearing member 1404 can then berotated in a selected direction, such as the direction indicated byarrow 1429 in FIG. 46, to move the tabs 1410 a-1410 c within the grooves1426 a-1426 c. The direction that the bearing member 1404 is moved canbe any appropriate direction, and the direction of arrow 1429 is merelyexemplary. The bearing member 1404 is inserted into the cage 1403 in aninsertion position and is rotated to an implanted or fixed position.

Once the bearing member 1404 is rotated to a selected or locked positionrelative to the cage 1403, a locking or set screw 1432 can be positionedin the second stem structure 1400 to fix or hold the bearing member 1404in the implanted position. The set screw 1432 can pass through orcooperate with a stem passage 1434 to engage or cooperate with a setregion 1436 of the bearing member 1404. The set region 1436 can includea cam or other appropriate surface to be engaged or contacted by the setscrew 1432.

The set screw 1432 can be positioned to resist rotation of the bearingmember 1404. In other words, the set screw can stop the bearing member1404 from returning to the insertion position, which is contrary to thedirection of the arrow 1429. Therefore, the bearing member 1404 can beheld within the cage 1403 by the tabs 1410 a-1410 c cooperating with therespective grooves 1426 a-1426 c of the cage 1403.

The bearing member 1404, therefore, can be a substantially modularbearing member that is selected for appropriate materials,configurations, sizes, and the like during an implantation procedure.For example, as discussed above, the bearing surfaces 1406 can include amultiple and angled bearing surface portions. A plurality of bearingmembers 1404 can be provided to include a plurality of angles betweenrespective central axes of the bearing surfaces defining the bearingsurface 1406. The user can select the bearing member 1404 prior to orduring a procedure based upon the patient's anatomy. Various otherpurposes for providing modular bearing members 1404 can also be providedand are discussed above.

With reference to FIGS. 48-50B, a second stem assembly 1500, accordingto various embodiments, is illustrated. The second stem structure 1500includes a second bearing component 1502 that includes a cage 1504 in abearing member 1506. The bearing member 1506 can be similar to thebearing member 1404, discussed above, including a bearing surface havingmultiple bearing surface configurations 1508 and a passage 1510. Thebearing member 1506, however, can differ from the bearing member 1404 atleast in that bearing member 1506 includes one or a plurality of grooves1518 a-1518 b that are part of a holding member or mechanism. Thegrooves 1518 a-1518 b can be defined below a surface or defined toextend from an exterior surface 1520 of the bearing member 1506. Thebearing member 1506 can also include tab entry regions 1522 a-1522 balso defined relative to the exterior surface 1520 of the bearing member1506.

The cage 1504 of the second bearing component 1502 can also be similarto the cage 1403 discussed above. The cage 1504 can include an interiorsurface 1530 with one or a plurality of tabs 1532 a and 1532 b that alsoform part of the holding member or mechanism. The bearing member 1506 ispositioned within the cage 1504 by moving the tabs 1532 a and 1532 binto the tab entry grooves 1522 a and 1522 b.

Once the bearing member 1506 is within the cage 1504, the bearing member1506 can be rotated in the direction of arrow 1536 illustrated in FIG.49, resulting in the tabs 1532 a-1532 b being positioned within thelocking or holding grooves 1518 a and 1518 b, as illustrated in FIGS.50A and 50B. The bearing member 1506 is inserted into the cage 1504 inan insertion position and then rotated to an implanted or fixedposition.

Once the bearing member 1506 is rotated to the selected lock orimplanted position, a locking or set screw 1540 can be passed through apassage or opening 1542 to hold or resist the bearing member 1506 fromrotating in a direction contrary to the arrow 1536. As discussed andillustrated above in FIG. 47B, the set screw 1432 of the second bearingcomponent 1402 can resist rotation of the bearing member 1404 and assistin holding the bearing member 1404 relative to the cage 1403. Similarly,the set screw 1540 can hold the bearing member 1506 in the selected orimplanted position relative to the cage 1504. The bearing member 1506can then be held within the cage 1504 by the interaction of the tabs1532 a and 1532 b with the grooves 1518 a and 1518 b. Further, in thedepicted embodiment, the locking or set screw 1540 can engage surface1544 to prevent rotation of the bearing member 1506. The locking or setscrews, according to various embodiments, can be part of the holding orlocking mechanism of the second bearing.

As discussed above, the second stem structure 1500 can be an ulnar stemstructure. The bearing surfaces 1508 of the bearing member 1506 candefine opposed dual spherical, semi-spherical or partially sphericalbearing surfaces. In addition, each of the opposing faces can define aplurality of bearing surfaces that include angled central axes, asdiscussed above. Accordingly, the second bearing component 1502 can beprovided as an ulnar bearing for an elbow prosthesis.

With reference to FIGS. 51-52B, a second stem structure 1600 isillustrated. The second stem structure 1600 can be provided as an ulnarprosthesis. The second stem structure 1600 includes a second bearingcomponent 1602 including a cage 1604 interconnected with or affixed tothe distal stem portion 1606.

The second bearing components 1602 can further include a bearing member1610 including selected portions, similar to the portions of the bearingmember 1404 discussed above. Generally, the bearing member 1610 caninclude a bearing surface 1612 or a plurality of bearing surfaces, suchas opposed at least partially spherical bearing surfaces. The bearingmember 1610 can further define a passage or bore 1614.

The bearing member 1610 includes one or more anti-rotation projections1616 a and 1616 b. Anti-rotation projection 1616 a and 1616 b canproject from an exterior surface 1618 of the bearing member 1610. Theexterior surface 1618 of the bearing member 1610 includes groove 1620.The groove 1620 can cooperate or hold a locking or fixation ring 1624relative to the bearing member 1610. The groove 1620 and the lockingring 1624 are a holding member or mechanism to assist in holding thebearing member 1610 within the cage 1604. The locking ring 1624 can alsooptionally include anti-rotation projections 1626 a and 1626 b.

Either the anti-rotation projections 1616 a and 1616 b or theanti-rotation projections 1626 a and 1626 b, can engage anti-rotationdepressions or grooves 1630 a and 1630 b included in an interior surface1632 of the cage 1604. Passage or entry region 1634 a and 1634 b canalso be defined in a sidewall of the cage 1604. The interior surface1632 includes a locking or fixation groove 1640 can also forms part ofthe holding member or mechanism.

The bearing member 1610 can be positioned in the cage 1604 before orafter the locking ring 1624 is positioned within the groove 1620 of thebearing member 1610. According to various embodiments, however, thelocking ring 1624 can be positioned within the locking ring groove 1620.The locking ring 1624 can then be compressed prior to or during movementof the bearing member 1610 and locking ring 1624 into the cage 1604.When the locking ring 1624 engages or is positioned near the groove1640, the locking ring 1624 can relax or expand to engage at least aportion of or move into a portion of a groove 1640.

The locking ring 1624 has a ring thickness 1644 allowing a first portionof the ring 1624 to be positioned within the groove 1640 and a secondportion of the ring 1624 to be positioned within the groove 1620substantially simultaneously. By positioning the locking ring 1624 inboth of the grooves 1620 and 1640, the locking ring 1624 holds thebearing member 1610 within the cage 1604. Thus, the locking ring 1624,alone, can be provided to hold the bearing member 1610 in the cage 1604.Other holding mechanisms can, however, be provided.

The anti-rotation projections, such as the anti-rotation projection 1616a and 1616 b, can assist in minimizing or eliminating rotation of thebearing member 1610 within the cage 1604. A set or locking screw 1646can, however, also be positioned within a passage 1648 defined in thesecond stem structure 1600 to engage an anti-rotation cam or surface1650 of the bearing member 1610. The set screw 1646 can also work as theholding member or mechanism. In this way, the bearing member 1610 can beheld, with respect to the cage 1604, both transversely, preventingmovement out of the cage 1604, and rotationally once the bearing member1610 is positioned within the cage 1604.

As discussed above, the bearing member 1610 can be provide as an ulnarbearing member, and the second stem assembly 1600 can be provided as anulnar prosthesis for implantation into a human patient. Accordingly, thebearing member 1610 can include the various features, discussed above.In addition, bearing member 1610 is modular or separate from the cage1604 and can provide for flexibility and selection by the user during aprocedure. For example, the kit can include a plurality of the bearingmembers 1610 each including different characteristics, such as differentbearing surfaces defined around central axes at varying angles. The usercan then select the appropriate bearing member for implantation into thepatient. Additionally, the modular members or portions allow fortrialing to determine or achieve the best or optimum configuration of aprosthesis during an operative procedure.

It will be understood that first and second stem structures and bearingcomponents are described according to various embodiments. The variousstem structures, however, can also be combined in selected andappropriate manners for a selected procedure. Thus, each stem structurecan be augmented to include any or all features discussed above.Similarly, each of the bearing components can be augments to include anyor all of the features discussed above.

With reference now to FIGS. 53-59, a linked stem assembly 1700 accordingto additional features is shown. The stem assembly 1700 can include anulna stem component 1702, a bearing member 1704, a ring member 1706(FIG. 54) and a fastener 1708. The ulna stem component 1702 can includean annular cage or enclosed structure 1710 that can couple with or holdthe bearing member 1704 in a selected position. The bearing member 1704can have a bearing surface 1712 that can include two faces or opposingpartially- or semi-spherical bearing surfaces. A throughbore or passage1714 can also be defined through the bearing member 1704. The bearingsurfaces 1712 and the passage 1714 can have any appropriateconfiguration, including those discussed above. In one example, thebearing surface 1712 can include two opposed bearing sections definedaround axes that are at an angle relative to one another.

The bearing member 1704 can include radially extending tabs 1716 a-1716c formed on an exterior surface 1718. In one example, the tabs 1716a-1716 c can extend to medial and lateral edges 1720 and 1722,respectively, of the bearing member 1704. Each tab 1716 a, 1716 b and1716 c are collectively defined by a pair of tabs 1716 a, 1716 b and1716 c separated by a depression 1719 a, 1719 b and 1719 c,respectively. A groove 1724 can be formed around the outer diameter ofthe bearing member 1704. In one example, the groove 1724 can begenerally centered between the medial and lateral edges 1720 and 1722 ofthe bearing member 1704. As will become appreciated, the groove 1724 isconfigured to at least partially receive the ring member 1706. The tabs1716 a-1716 c can be positioned 120° apart around the bearing member1704. The tabs 1716 a-1716 c can extend at a height 1726 above theexterior surface 1718 of the bearing member 1704. The bearing member1704 can be formed of ultra high molecular weight polyethylene (UHMWPE)or polyetheretherketone (PEEK).

The tabs 1716 a-1716 c can pass through corresponding tab entries 1730a-1730 c formed in a sidewall 1732 of the annular cage 1710. Thesidewall 1732 can extend between a medial edge 1734 and a lateral edge1736 of the annular cage 1710. A groove 1738 can be formedconcentrically around the inner diameter or sidewall 1732 of the annularcage 1710. In one example, the groove 1738 can be generally centeredbetween the medial edge 1734 and the lateral edge 1736. As will bediscussed herein, the bearing member 1704 can be held within the annularcage 1710 with the ring member 1706 partially nesting into the groove1724 provided on the bearing member 1704 and the groove 1738 provided onthe annular cage 1710.

The ulna stem component 1702 can include a radially compressible lockingmechanism 1739. The radially compressible locking mechanism 1739includes a disconnect or cut 1740 formed completely through the annularcage structure 1710 from an outer surface 1742 to the sidewall 1732. Inone example, the cut 1740 can be machined in a subsequent step aftermachining the ulna stem component 1702. The radially compressiblelocking mechanism 1739 can also include a threaded fastener passage 1744that is provided in the ulna stem component 1702 and traverses the cut1740. A counter-bore 1746 can be formed on the ulna stem component 1702for nestingly receiving the fastener 1708. As will become appreciatedfrom the following discussion, the annular cage 1710 is configured toslightly expand the sidewall 1732 radially outwardly during assembly ofthe bearing member 1704 and subsequently retract radially inwardly uponadvancement of the fastener 1708 through the fastener passage 1744 inthe assembled position.

With specific reference to FIGS. 55-59, an exemplary method ofassembling the bearing member 1704 into the annular cage 1710 of theulna stem component 1702 will now be discussed. Initially, the bearingmember 1704 can be selected from a group or kit of bearing members, suchthat an appropriate material, configuration, size and other material orgeometrical considerations can be satisfied. For example, as discussedabove, the bearing surfaces 1712 can include a multiple and angledbearing surface portion. A plurality of bearing members 1704 can beprovided to include a plurality of angles between respective centralaxes of the bearing surfaces defining the bearing surface 1712. The usercan select the bearing member 1704 prior to or during a procedure basedupon the patient's anatomy. Various other purposes for providing modularbearing members 1704 can also be provided and are discussed above.

Once the desired bearing member 1704 has been selected, the ring member1706 can be positioned at least partially into the groove 1724 formed onthe bearing member 1704 (FIG. 55). In some examples, the ring member1706 can be slightly expanded radially outwardly to advance past thetabs 1716 a-1716 c until reaching a location aligned with the groove1724. Next, a surgeon can positively align the tabs 1716 a-1716 c of thebearing member 1704 with the tab entries 1730 a-1730 c of the ulna stemcomponent 1702. The lateral edge 1722 of the bearing member 1704 canthen be advanced past the medial edge 1734 of the ulna stem component1702 until a position where the ring member 1706 comes into contact withthe medial edge 1734 of the ulna stem component 1702. At this point, asurgeon can compress manually the ring member 1706 further into thegroove 1724 on the bearing member 1704 and/or, continue to advance thebearing member 1704 into the annular cage 1710 causing the ring member1706 to compress further into the groove 1724 and reach an outerdiameter that is generally less than the inner diameter of the sidewall1732 (FIG. 56). The bearing member 1704 is then further advanced intothe annular cage 1710 until reaching a position where the ring member1706 aligns with the groove 1738 formed around the sidewall 1732 of theannular cage 1710. Once the ring member 1706 aligns with the groove 1738on the sidewall 1732, the ring member 1706 will expand radiallyoutwardly to its original static position where at least a portion ofthe ring member 1706 extends into the groove 1738 of the annular cage1710 and at least partially extends into the groove 1724 of the bearingmember 1704 (FIG. 57).

Next, with specific reference to FIGS. 58 and 59, the radiallycompressible locking mechanism 1739 will be further described. Thefastener 1708 is threadably advanced into the fastener passage 1744 ofthe ulna stem component 1702. Threadable advancement of the fastener1708 into the fastener passage 1744 causes the inner diameter of thesidewall 1732 to be reduced as a gap 1748 defined by opposing sidewallsof the cut 1740 closes. Once the fastener 1708 has been advancedsufficiently to close the gap provided by the cut 1740, the ring member1706 becomes further nested within each of the grooves 1724 and 1738 ofthe bearing member 1704 and the annular cage 1710, respectively. In theassembled position, the ring member 1706 inhibits medial/lateral motionof the bearing member 1704 relative to the sidewall 1732 of the annularcage 1710. Additionally, the tabs 1716 a-1716 c of the bearing member1704 cooperate with the tab entries 1730 a-1730 c to inhibit rotationalmotion of the bearing member 1704 within the annular cage 1710. The stemassembly 1700 can be used in conjunction with any of the bearing and/orstem components described herein. While the radially compressiblelocking mechanism 1739 has been described as compressing the annularcage 1710 by advancement of the fastener 1708 into the fastener passage1744, other configurations and mechanisms may be employed to compressthe annular cage 1710 around the bearing member 1704.

With reference now to FIG. 60, an ulna stem component 1702′ constructedin accordance to additional features of the present teachings will nowbe described. Unless otherwise described, the ulna stem component 1702′is constructed similarly to the ulna stem component 1702 discussed abovewith respect to FIGS. 54-59. The ulna stem component 1702 can include anannular cage or enclosed structure 1710′ that can couple with or holdthe bearing member 1704 (not specifically shown in this figure) in aselected position. The annular cage 1710′ can have an inner cylindricalsidewall 1732′ that extends between a medial edge 1734′ and a lateraledge 1736′. The ulna stem component 1702′ can have a disconnect or cut1740′ that is formed completely through the annular cage structure 1710′from an outer surface 1742′ to the sidewall 1732′. The cut 1740′ of theulna stem component 1702′ has a V-shaped profile. The V-shaped profiledecreases shear loads experienced on the ulna stem component 1702′. Inthis way, any shear loads experienced between a bearing member 1704assembled in the annular cage 1710′ and the ulna stem component 1702′can be taken up by not only the fastener 1708 but by the structure ofthe ulna stem component 1702′ as a result of the opposing surfacescreated by the V-shaped profile in the cut 1740′. It will be appreciatedthat the cut 1740′ having the V-shaped profile can be included on any ofthe ulna stem components disclosed herein.

With reference now to FIGS. 61-67, a linked stem assembly 1800 accordingto additional features is shown. The stem assembly 1800 can include anulna stem component 1802, a bearing member 1804, and a fastener 1808.The ulna stem component 1802 can include an annular cage or enclosedstructure 1810 that can couple with or hold the bearing member 1804 (orthe bearing member 1804′) in a selected position. The bearing member1804 can have a bearing surface 1812 that can include two faces oropposing partially- or semi-spherical bearing surfaces. The throughboreor passage 1814 can also be defined through the bearing member 1804. Thebearing surfaces 1812 and the passage 1814 can have any appropriateconfiguration, including those discussed above. In one example, thebearing surface 1812 can include two bearing sections defined aroundaxes that are at an angle relative to one another. The bearing member1804′ can have similar features as the bearing member 1804. In this way,similar features are simply identified with a “prime” suffix on thereference numeral.

The bearing member 1804 can include tabs 1816 a-1816 c formed on anexterior surface 1818. In one example, the tabs 1816 a-1816 c can extendto medial and lateral edges 1820 and 1822, respectively, of the bearingmember 1804. A radial depression 1824 can be formed around the outerdiameter of the bearing member 1804. In one example, the radialdepression 1824 can be in the form of a negative V-shape. The tabs 1816a-1816 c can radially extend at a height 1826 above the exterior surface1818 of the bearing member 1804. The bearing member 1804 can be formedof ultra high molecular weight polyethylene (UHMWPE) orpolyetheretherketone (PEEK).

The tabs 1816 a-1816 c can pass through tab entries 1830 a-1830 c formedin a sidewall 1832 of the cage 1810 and rest therein. The sidewall 1832can extend between a medial edge 1834 and a lateral edge 1836 of thecage 1810. A radial protrusion 1838 can be formed around the innerdiameter or sidewall 1832 of the cage 1810. In one example, the radialprotrusion 1838 can be in the form of a positive V-shape. In oneexample, the radial protrusion 1838 can be generally centered betweenthe medial edge 1834 and the lateral edge 1836. As will be describedherein, the radial depression 1824 formed on the bearing member 1804 cannestingly receive the radial protrusion 1838 formed on the sidewall 1832of the cage 1810 to positively locate the bearing member 1804 inside thecage 1810.

The ulna stem component 1802 can include a radially compressible lockingmechanism 1839. The radially compressible locking mechanism 1839includes a disconnect or cut 1840 formed completely through the annularcage structure 1810 from an outer surface 1842 to the sidewall 1832.Again, the cut 1749 may be formed through the cage structure 1810 by asupplemental machining step. The radially compressible locking mechanism1839 can include a threaded fastener passage 1844 that is provided inthe ulna stem component 1802 and traverses the cut 1749. A counter-bore1846 can be formed on the ulna stem component 1802 for nestinglyreceiving the fastener 1808. As will become appreciated from thefollowing discussion, the cage 1810 is configured to slightly expand thesidewall 1832 radially outwardly during assembly of the bearing member1804 and subsequently retract radially inwardly upon advancement of thefastener 1808 through the fastener passage 1844 in the assembledposition.

With specific reference now to FIGS. 63-65, an exemplary method ofassembling the bearing member 1804 into the cage 1810 of the ulna stemcomponent 1802 will be discussed. Initially, the bearing member 1804 canbe selected from a group or kit of bearing members (such as includingthe bearing member 1804′), such that an appropriate material,configuration, size and other material or geometrical considerations canbe satisfied. For example, as discussed above, the bearing surfaces 1812can include a multiple and angled bearing surface portion. A pluralityof bearing members 1804 can be provided to include a plurality of anglesbetween respective central axes of the bearing surfaces defining thebearing surface 1812. The user can select the bearing member 1804 priorto or during a procedure based upon the patient's anatomy. Various otherpurposes for providing modular bearing members 1804 can also be providedand are discussed above.

Once the desired bearing member 1804 has been selected, a surgeon canalign the tabs 1816 a-1816 c of the bearing member 1804 with the tabentries 1830 a-1830 c of the ulna stem component 1802. The lateral edge1822 of the bearing member 1804 can then be advanced passed the medialedge 1834 of the ulna stem component 1802 until a position where theradial protrusion 1838 of the cage 1810 is aligned with the radialdepression 1824 of the bearing member 1804. Because the radialprotrusion 1838 is in the form of a positive V-shape and the radialdepression 1824 is in the form of a complementary negative V-shape, auser is given positive tactile feedback when the radial protrusion 1838is satisfactorily received into the radial depression 1824 of thebearing member 1804. It will be appreciated by those skilled in the artthat while the radial depression 1824 has been described as beingprovided on the bearing member 1804 and the radial protrusion 1838 hasbeen described as being provided on the cage 1810, the respectivedepression and protrusion may be located on opposite components.Furthermore, while the respective depression 1824 and protrusion 1838have been illustrated and described as having a V-shape geometry, othergeometries may be provided that can establish a complementaryinterlocking profile.

Next, with specific reference to FIGS. 66 and 67, the radiallycompressible locking mechanism 1839 will be further described. Thefastener 1808 can be threadably advanced into the fastener passage 1844of the ulna stem component 1802. Threadable advancement of the fastener1808 into the fastener passage 1844 causes the inner diameter of thesidewall 1832 to be reduced as a gap 1848 defined by the cut 1840closes. Once the fastener 1808 has been advanced sufficiently to closethe gap provided by the cut 1840, the bearing member 1804 is furthersecured in a confined position within the cage 1810. In the assembledposition, the interface between the radial depression 1824 and theradial protrusion 1838 inhibits medial/lateral motion of the bearingmember 1804 relative to the sidewall 1832 of the cage 1810.Additionally, the tabs 1816 a-1816 c of the bearing member 1804cooperate with the tab entries 1830 a-1830 c to inhibit rotationalmotion of the bearing member 1804 within the cage 1810. The stemassembly 1800 can be used in conjunction with any of the bearing and/orstem components described herein. While the radially compressiblelocking mechanism 1839 has been described as compressing the cage 1810by advancement of the fastener 1808 into the fastener passage 1844,other configurations and mechanisms may be employed to compress the cage1810 around the bearing member 1804.

With reference now to FIGS. 68-72, a modular unlinked ulnar stemassembly 1900 according to one example of the present teachings will bedescribed. In general, the modular unlinked ulnar stem assembly 1900 caninclude a stem 1902, an articulating component 1904, a plate 1906 and afastener 1908. As will become appreciated from the following discussion,the articulating component 1904 can be modular such that a series ofarticulating components can be provided that are selectively attachableto the stem 1902 according to a specific patient's needs. The modularunlinked ulnar stem assembly 1900 can be favorable in some circumstancesas it has the potential to remove less native bone than other elbowprostheses such as a semi-constrained total elbow, for example.Furthermore, the modular unlinked ulnar stem assembly 1900 can befavorable in circumstances where one side of the elbow joint includessatisfactory bone and/or cartilage and it is only desirable to replacethe other side of the elbow joint.

With specific reference now to FIG. 69, exemplary features of the stem1902 will be described. The stem 1902 can generally include an ulnarring 1910 that is in the form of a partial or semi-circular cylinder.The stem 1902 can further comprise a first retaining mechanism 1912having laterally extending rails 1914 that extend around the ulnar ring1910 from a first end 1916 to a second end 1918. The second end 1918 ofthe rails 1914 can include a stop 1920 that has a pair of outwardlyextending stop surfaces 1922. The ulnar ring 1910 can also include aconcave slide surface 1924 and a threaded bore 1926 formed thereon.

With continued reference to FIG. 69, the articulating component 1904will be described in greater detail. In general, the articulatingcomponent 1904 can include a body 1930 that generally takes the shape ofa partial or semi-circular cylinder complementary to the shape of theulnar ring 1910. The articulating component 1904 includes a secondretaining mechanism 1932 having a pair of lateral walls 1934 thatcooperate to define a semi-circular arcuate channel 1936. The lateralwalls 1934 extend from a first end 1938 to a second end 1940. A pair ofcatches 1942 are formed at the respective second ends 1940 of the arms1934. The catches 1942 have catch surfaces 1944. The articulatingcomponent 1904 includes a convex slide surface 1948 that extends betweenthe respective lateral arms 1934. The articulating component 1904 can beformed of ultra high molecular weight polyethylene (UHMWPE) orpolyetheretherketone (PEEK).

Turning now to FIGS. 70-72, an exemplary method of attaching thearticulating component 1904 to the stem 1902 will be described. At theoutset, once a surgeon has selected the appropriate articulatingcomponent 1904 that satisfies a desired articulating surface geometryfor a particular patient, the second end 1940 is located generallyadjacent to the first end 1916 of the rails 1914 of the stem 1902 (FIG.70). Next, the surgeon rotates the articulating component 1904 in acounter-clockwise direction about an axis 1950 (as viewed in FIGS.70-71) such that the rails 1914 of the first retaining mechanism 1912locate into the channel 1936 of a second retaining mechanism 1932.Continued rotation of the articulating component 1904 around the rails1914 can additionally include slidable engagement of the convex slidesurface 1948 of the articulating component 1904 along the concave slidesurface 1924 of the ulnar ring 1910. The articulating component 1904 isfurther rotated until the catch 1942 on the articulating component 1904engages the stop 1920 provided on the second end 1918 of the rails 1914.In this way, the catch surfaces 1944 of the articulating component 1904can rest on the stop surfaces 1922 of the rails 1914 (FIG. 72). Next, asurgeon can advance the fastener 1908 through a passage 1954 (as bestshown in FIG. 69) of the plate 1906 and threadably advance the fastener1908 into the threaded bore 1926 of the stem 1902 to capture and retainthe articulating component 1904.

With reference now to FIGS. 73-77, another exemplary modular unlinkedulnar stem assembly 2000 constructed in accordance to additionalfeatures of the present teachings will be described. The modularunlinked ulnar stem assembly 2000 can generally comprise a stem 2002, anarticulating component 2004, an intermediate rail component 2006, and afastener 2008. The drawings depict the articulating component 2004 andthe intermediate rail component 2006 as separate for illustrativepurposes. The articulating component 2004 and the intermediate railcomponent 2006 are molded together as a single piece. The stem 1902 caninclude an ulnar ring 2010 that is generally in the shape of a partialor semi-circular cylinder. The stem 2002 can include a first retainingmechanism 2012 that includes a groove 2014 formed in the ulnar ring2010. A lip 2016 is provided at a terminal end of the groove 2014 on thefirst retaining mechanism 2012. The ulnar ring 2010 can further comprisea threaded bore 2026.

As with the configurations described above, the articulating component2004 can be modular. In this way, a series of articulating componentscan be provided that each have various geometries that can be selectedaccording to a particular patient's needs. Furthermore, while thearticulating component 2004 and the rail component 2006 are shown asdistinct components, they may be provided as an integrally formed piece.In one example, the rail component 2006 can be formed of biocompatiblemetal material such as titanium and the articulating component 2004 canbe formed of UHMWPE or PEEK. As described above, in one example, therail component 2006 can be molded to the articulating component 2004.Other techniques may be utilized to connect the rail component 2006 tothe articulating component 2004.

The rail component 2006 can generally comprise a second retainingmechanism 2032 in the form of a rail 2036. The second retainingmechanism 2032 can further comprise a finger 2038 that is formed at aterminal end of the rail 2036. On an end opposite of the finger 2038,the rail component 2006 can include a plate 2040 having an eyelet 2042formed there through. The rail component 2006 includes an annularchannel 2044 that can facilitate molding with the articulating component2004.

With specific reference now to FIG. 75, another modular unlinked ulnarstem assembly 2000′ is shown. Like features are illustrated with similarreference numerals as shown and described above with respect to FIG. 74and having a “prime” suffix. The stem assembly 2000′ can include a railcomponent 2006′ shown having a second retaining mechanism 2032′ thatincludes a rail 2036′ and a finger 2038′. An eyelet 2042′ is provided onthe rail component 2006′. The articulating component 2004′ and the railcomponent 2006′ are shown as separate pieces however they are moldedtogether as a single unit.

Turning now to FIGS. 76 and 77, an exemplary method of assembling thearticulating component 2004 to the ulnar ring 2010 of the stem 2002 willbe described. In the examples shown in FIGS. 76 and 77, the articulatingcomponent 2004 and the rail component 2006 are shown as an integralpiece. At the outset, a rail 2036 of the rail component 2006 is alignedfor receipt into the groove 2014 provided on the ulnar ring 2010. Next,the articulating component 2004 and rail component 2006 are advancedinto contact with the first retaining mechanism 2012 of the stem 2002.Explained further, the rail 2036 is advanced into the groove 2014 whilethe finger 2038 locates around the lip 2016 on the ulnar ring 2010. Atthis point, the fastener 2008 is advanced through the eyelet 2042 andthreadably advanced into the threaded bore 2026. As can be appreciated,the first and second retaining mechanisms 2012 and 2032 cooperate tomaintain the articulating component 2004 in a secure position.

With reference now to FIGS. 78 and 79, another modular unlinked ulnarstem assembly 2100 according to additional features of the presentteachings will be described. The modular unlinked ulnar stem assembly2100 can generally include a stem 2102, an articulating component 2104,and a fastener 2108. The articulating component 2104 further comprises arail 2136. The stem 2102 can include an ulnar ring 2110 that isgenerally in the form of a partial cylinder and has a catch 2120 formedat an end thereof. A groove 2114 is formed in the ulnar ring 2110. Inone example, the catch 2120 can cooperate with the fastener 2108 toprovide a first retaining mechanism 2112. The articulating component2104 can include a second retaining mechanism 2132 that includes a footportion 2140 formed at an opposite end of a neck portion 2142. Accordingto one example of assembling the articulating component 2104 to theulnar ring 2110 of the stem 2102, the articulating component 2104 can berotated in a counter-clockwise direction as viewed in FIG. 78 until thefoot portion 2140 engages the catch 2120. Next, the fastener 2108 isthreadably advanced into the threaded bore 2126 to further capture thearticulating component 2104 relative to the ulnar ring 2110 of the stem2102.

With reference now to FIGS. 80 and 81, another unlinked ulnar stemassembly 2200 according to additional features of the present teachingswill be described. The unlinked ulnar stem assembly 2200 can beconfigured to be inserted into a prepared opening 2202 of an ulna 2204.The unlinked ulnar stem assembly 2200 generally comprises a body portion2210 and a C-shaped support frame 2212. The body portion 2210 can be inthe form of a stem structure 2213 that includes a stem portion 2214. Thebody portion 2210 can have a retaining mechanism 2220 formed thereon.The retaining mechanism 2220 can generally include a first portion orlongitudinal member 2222 and a second portion or longitudinal member2224. An articulating component 2226 can be connected to the C-shapedsupport frame 2212. In one example, the first longitudinal member 2222can generally be in the form of an elongated planar member extending ina superior/inferior direction. The first longitudinal member 2222 canhave a first medial/lateral dimension 2228. The second longitudinalmember 2224 can generally be in the form of an elongated planar memberthat is transverse to the first longitudinal member 2222 and extendsgenerally in the medial/lateral direction. The second longitudinalmember 2224 can have a second medial/lateral dimension 2229. The seconddimension 2229 is greater than the first dimension 2228.

The first and second longitudinal members 2222 and 2224, respectively,can cooperate to provide a T-shaped cross-section of the retainingmechanism 2220. In one example, the body portion 2210 can be formed ofbiocompatible metal material, such as titanium. The articulatingcomponent 2226 can be formed of UHMWPE or PEEK. According to oneconfiguration, the articulating component 2226 can be molded to theC-shaped support frame 2212. Other methods may be used to interconnectthe articulating component 2226 with the C-shaped support frame 2212. Itis also contemplated that the articulating component 2226 can be modularrelative to the C-shaped support frame 2212. In this way, in someexamples, a surgeon may select an articulating component 2226 havingproperties suitable for a given patient's needs and intraoperativelyconnect the articulating component 2226 with the C-shaped support frame2212.

With continued reference to FIGS. 80 and 81, the ulna 2204 will bedescribed in greater detail. The ulna 2204 can be shaped to include aC-shaped receiving portion 2230 that has a geometry suitable to receivethe C-shaped support frame 2212 of the unlinked ulnar stem assembly2200. The opening 2202 can be formed, such as with a punch, reamer orother drilling device that is operable to form a cavity having a shapethat is complementary with the retaining mechanism 2220. In this way,the opening 2202 generally has a first longitudinal cavity portion 2232and a second longitudinal cavity portion 2234 that collectively providesan elongated T-shaped cavity for receiving the stem structure 2212 andretaining mechanism 2220 of the unlinked ulnar stem assembly 2200 asshown in FIG. 81. In one example, bone cement may be used in the opening2202. Additionally, or alternatively, the outer surface of the retainingmechanism 2220 can be porous for facilitating boney ingrowth.

As best illustrated in FIG. 81, the second longitudinal member 2224 canbe confined within the first longitudinal cavity portion 2232 to inhibitmovement of the unlinked stem assembly 2200 in an anterior directionwhen implanted into the ulna 2204. The unlinked stem assembly 2200 isalso inhibited from movement in other directions, such as the medial andlateral directions upon receipt into the opening 2202. It is appreciatedthat the T-shaped cross-section of the retaining mechanism 2220 and thecorresponding opening 2202 may be formed differently. Othercross-sections are contemplated, such as a dove-tail cross-section, acurved cross-section or other cross-sections suitable to provide asecure relationship between the retaining mechanism 2220 and the opening2202.

With reference now to FIGS. 82 and 83, another unlinked ulnar stemassembly 2250 according to additional features of the present teachingswill be described. The unlinked ulnar stem assembly 2250 can beconfigured to be inserted into a prepared opening 2252 of an ulna 2204.The unlinked ulnar stem assembly 2250 generally comprises a body portion2260 and a C-shaped support frame 2262. The body portion 2260 can be inthe form of a stem structure 2263 that includes a stem portion 2264. Thebody portion 2260 can have a retaining mechanism 2270 formed thereon.The retaining mechanism 2270 can generally include a first portion orlongitudinal member 2272 and a second portion or longitudinal member2274. The second longitudinal member 2274 can generally be in the formof a cylinder 2275. An articulating component 2276 can be connected tothe C-shaped support frame 2262. In one example, the first longitudinalmember 2272 can generally be in the form of an elongated planar memberextending in a superior/inferior direction. The first longitudinalmember 2272 can have a first medial/lateral dimension 2277. The cylinder2275 of the second longitudinal member 2274 can have portions thatextend in a direction that is transverse to the first longitudinalmember 2272. The second longitudinal member 2274 can have a secondmedial/lateral dimension 2278. The second dimension 2278 is greater thanthe first dimension 2277. The retaining mechanism 2270 can thereforeprovide a substantially non-linear cross-section.

In one example, the body portion 2260 can be formed of biocompatiblemetal material, such as titanium. The articulating component 2276 can beformed of UHMWPE or PEEK. According to one configuration, thearticulating component 2276 can be molded to the C-shaped support frame2262. Other methods may be used to interconnect the articulatingcomponent 2276 with the C-shaped support frame 2262. It is alsocontemplated that the articulating component 2276 can be modularrelative to the C-shaped support frame 2272. In this way, in someexamples, a surgeon may select an articulating component 2276 havingproperties suitable for a given patient's needs and intraoperativelyconnect the articulating component 2276 with the C-shaped support frame2262.

With continued reference to FIGS. 82 and 83, the ulna 2254 will bedescribed in greater detail. The ulna 2254 can be shaped to include aC-shaped receiving portion 2280 that has a geometry suitable to receivethe C-shaped support frame 2262 of the unlinked ulnar stem assembly2250. The opening 2252 can be formed, such as with a punch, reamer, orother drilling device that is operable to form a cavity having a shapethat is complementary with the retaining mechanism 2270. In this way,the opening 2252 generally has a first longitudinal cavity portion 2282having a cylindrical cross-section, and a second longitudinal cavityportion 2284 having a generally planar cross-section that collectivelyprovide a shape that is suitable for receiving the stem structure 2263and retaining mechanism 2270 of the unlinked ulnar stem assembly 2250 asshown in FIG. 82. Once the retaining mechanism 2270 is suitably insertedinto the opening 2252, a bone screw 2240 is inserted into a throughbore2242 provided in the cylinder 2275. The bone screw 2240 is thenthreadably advanced into the ulna 2254 until a head 2244 of the bonescrew 2240 rests on a counterbore ledge 2246 formed in the cylinder2275.

In one example, bone cement may be used in the opening 2252.Additionally, or alternatively, the outer surface of the retainingmechanism 2270 can be porous for facilitating bony ingrowth. As bestillustrated in FIG. 83, the second longitudinal member 2274 can beconfined within the first longitudinal cavity portion 2282 to inhibitmovement of the unlinked ulnar stem assembly 2250 in an anteriordirection when implanted into the ulna 2254. The unlinked ulnar stemassembly 2250 is also inhibited from movement in other directions, suchas the medial and lateral directions upon receipt into the opening 2252.It is appreciated that the cylindrical shaped cross-section of thesecond longitudinal member 2274 of the retaining mechanism 2270 and thecorresponding opening 2254 may be formed differently.

With reference now to FIGS. 84 and 85, a bearing removal tool kit 2300constructed in accordance to additional features of the presentteachings will be described. In general, the bearing removal tool kit2300 can include a series of tools that, in various combinations, can beused to assist a surgeon in compressing a lock ring 2302 (FIG. 85) suchthat a bearing member 1704 can be subsequently urged (in themedial/lateral direction) out of an annular cage 1710 of an ulna stemcomponent 1702. As will be described, while the bearing removal tool kit2300 is shown cooperating with the lock ring 2302 and ulna stemcomponent 1702, the various tools of the bearing removal tool kit 2300can be used to compress lock rings having different configurations, suchas shown herein at reference numeral 1706 (FIG. 54) or at referencenumeral 1624 (FIG. 51). Likewise, while the bearing removal tool kit2300 is shown for use during removal of the bearing member 1704, thebearing removal tool kit 2300 can be used to urge other bearing membershaving various shapes, such as disclosed herein including the bearingmember 1610 (FIG. 51).

The bearing removal tool kit 2300 can generally comprise a first tool2310, a second tool 2312, a third tool 2314, a series of extractor pins2316 and an extractor plate 2318. The first tool 2310 can generally takethe shape of forceps and, as will be described, can be used to hold andposition the extractor pins 2316 relative to the ulna stem component1702 and the bearing member 1704. The first tool 2310 can include afirst arm 2320 having a first handle 2322 at one end and a half ring2324 on an opposite end. A second arm 2326 can have a second handle 2328at one end and a half ring 2330 at an opposite end. A pair of lockingmembers 2332 and 2334 can be formed on the first handle 2322 and thesecond handle 2328, respectively. The first and second arms 2320 and2326 can be pivotally coupled at a pivot 2336. The opposed half rings2324, 2330 have opposed arcuate surfaces that engage a cylindrical neck2392 of the pins 2316 as will be described.

The second tool 2312 can be used to further urge the extractor pins 2316between the annular cage 1710 of the ulna stem component 1702 and thebearing member 1704 as shown in FIGS. 87 and 88. The second tool 2312can also be generally in the form of forceps. The second tool 2312 canhave a first arm 2340 having a first handle 2342 at one end and anelongated locating finger 2344 at an opposite end. The locating finger2344 can include a nub 2345 provided thereon. The second tool 2312 canfurther include a second arm 2346 having a second handle 2348 at one endand a rectangular locating pad 2350 at an opposite end. The locating pad2350 can define a recess 2352. The first and second arms 2340 and 2346can be pivotally coupled at a pivot 2356.

The third tool 2314 can be used to urge the bearing member 1704 out ofthe annular cage 1710 once the lock ring 2302 has been compressed asshown in FIGS. 91 and 92. The third tool 2314 can also take the generalshape of forceps. The third tool 2314 can include a first arm 2360having a first handle 2362 at one end and a rectangular locating pad2364 at an opposite end. The third tool 2314 can also have a second arm2366 having a second handle 2368 at one end and a spherical plunger 2370at an opposite end. The first and second arms 2360 and 2366 can bepivotally coupled at a pivot 2372.

The extractor pin 2316 can be used to slidably advance between theannular cage 1710 of the ulna stem component 1702 and the bearing member1704. During such slidable advancement, the extractor pin 2316 can rampover an outer radial surface of the lock ring 2302 to compress the lockring 2302 as will be further described. The extractor pin 2316 generallyincludes a shaft 2378 that has a first end 2380 and a second end 2382.The first end 2380 can have an interference portion 2384 in the generalshape of a conical tip. The second end 2382 can include a head 2386 thatincludes a first collar 2388, a second collar 2390 and a cylindricalneck 2392 therebetween.

The extractor plate 2318 can be used similarly to the extractor pins2316 when it is desired to concurrently or simultaneously advance aseries of extractor pins between the annular cage 1710 of the ulna stemcomponent 1702 and the bearing member 1704 instead of sequentiallylocating individual extractor pins 2316. In general, the extractor plate2318 includes a plate body 2394 having a plurality of extractor pins2396 extending from a first surface 2398 of the plate body 2394. Each ofthe extractor pins 2396 includes first ends 2400 having interferenceportions 2402.

With reference now to FIGS. 85 and 86, initial positioning of theextractor pins 2316 with the first tool 2310 will be described accordingto one example. Again, it will be appreciated that while the first tool2310 is being described as initially locating the extractor pins 2316,the extractor pins 2316 may be initially located with other tools orsimply by a surgeon's fingers. At the outset, the half rings 2324 and2330 of the first tool 2310 can be located around the neck 2392 at thesecond end 2382 of the extractor pin 2316. Next, the first end 2380 ofthe extractor pin 2316 can be advanced into the depression 1719 bbetween the tabs 1716 b of the bearing member 1704. According to oneexample, the extractor pin 2316 can be advanced in the medial/lateraldirection a distance until initially engaging the lock ring 2302. Whilethe second tool 2312 is described herein as further advancing theextractor pin to compress the lock ring 2302, it is contemplated that insome examples, the first tool 2310 can optionally be used to furtheradvance the extractor pins 2316 to compress the lock ring.

With reference now to FIGS. 87 and 88, the second tool 2312 of thebearing removal tool kit 2300 will be described as further advancing theextractor pins 2316 between the annular cage 1710 of the ulna stemcomponent 1702 and the bearing member 1704 to compress the lock ring2302. Initially, the recess 2352 of the locating pad 2350 can be placedaround the first collar 2388 of the second end 2382 of the extractor pin2316. The nub 2345 of the locating finger 2344 can also be located atthe depression 1719 b. The first end second handles 2342 and 2348 canthen be urged together, such that the first and second arms 2340 and2346 rotate or pivot around the pivot 2356 to create a clamping forcebetween the locating finger 2344 and the locating pad 2350. The clampingforce causes the interference portion 2384 of the extractor pin 2316 toramp across a radial outer surface 2410 of the lock ring 2302 andthereby compress the lock ring 2302 into the groove 1724 of the bearingmember 1704. Once all of the extractor pins 2316 have been advanced, thelock ring 2302 will be compressed into the groove 1724 and thereforemoved to a position out of the groove 1738 of the ulna stem component1702. According to other methods, one extractor pin 2316 can be slidablyadvanced in the medial (or lateral) direction through the depression1719 b to the position shown in FIG. 88. Next, another longitudinalmember (i.e., a pin, nail, shaft, etc.) can be slidably advanced in theopposite direction through the same depression 1719 b to push out andtake the place of the extractor pin 2316. In such a method, only oneextractor pin 2316 is needed as it can be used in sequence through allof the depressions 1719 a, 1719 b and 1719 c. It is also appreciatedthat while three depressions 1719 a, 1719 b and 1719 c have beendescribed as receiving three extractor pins 2316, using more or lessextractor pins and depressions are contemplated.

With reference now to FIGS. 89 and 90, an alternate method ofcompressing the lock ring 2302 using the extractor plate 2318 will bedescribed. Again, the extractor plate 2318 can be used when it isdesired to concurrently or simultaneously pass a series of pins betweenthe annular cage 1710 of the ulna stem component 1702 and the bearingmember 1704. When using the extractor plate 2318, a surgeon caninitially position the respective first ends 2400 of the extractor pins2396 into the corresponding depressions 1719 a, 1719 b and 1719 c of thebearing member 1704. Next, the plate body 2394 of the extractor plate2318 can be advanced further between the annular cage 1710 of the ulnastem component 1702 and the bearing member 1704. In doing so, therespective interference portions 2402 slidably advance along the outersurface 2410 of the lock ring 2302 causing it to compress into thegroove 1724 of the bearing member 1704. By compressing the lock ring2302 into the groove 1724 of the bearing member 1704, the lock ring 2302is moved to a position away from the groove 1738 in the ulna stemcomponent 1702. The extractor plate 2318 can be advanced in themedial/lateral direction by any suitable clamping instrument, such asthose disclosed herein or by urging with a surgeon's fingers.

With reference now to FIGS. 91 and 92, use of the third tool 2314 tourge the bearing member 1704 out of the annular cage 1710 after the lockring 2302 has been compressed will be described. In one example, thelocating pad 2364 of the first arm 2360 can be located on one side ofthe ulna stem component 1702 and the plunger 2370 can be located on theopposite side of the ulna stem component 1702 and centrally aligned andnested into the bearing member 1704. In one example, a nub similar tothe nub 2345 (FIG. 87) can be included on the locating pad 2364 forlocating into the depression 1719 b (FIG. 86). The plunger 2370 can beformed entirely or partially of resilient material. The plunger 2370 caninclude a metallic substrate having a nylon coating or be formedentirely of a metallic substrate. In other examples, a polymericmaterial can be provided on the plunger 2370. Next, the first and secondhandles 2362 and 2368 (see FIG. 84) can be urged together, such that thefirst and second arms 2360 and 2366 pivot around the pivot 2372 andcreate a clamping force between the locating pad 2364 and the plunger2370. As a result, the plunger 2370 forcibly advances the bearing member1704 in the medial/lateral direction out of the annular cage 1710 asshown in FIG. 92. Once the bearing member 1704 is urged out of theannular cage 1710, the extractor pins 2316 will simply fall away fromthe annular cage 1710 and can be later collected.

While the description in the specification and illustrated in thedrawings are directed to various embodiments, it will be understood thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the teachings andthe appended claims. In addition, many modifications may be made toadapt a particular situation or material to the teachings withoutdeparting from the scope thereof. Therefore, it is intended that theteachings and claims are not be limited to any particular embodimentillustrated in the drawings and described in the specification, but thatthe teachings and claims can include any embodiments falling within theforegoing description and the appended claims.

What is claimed:
 1. A joint prosthesis comprising: a first stemstructure including a generally U-shaped portion having a first leg anda second leg; a second stem structure including a first bearing surfaceand a second bearing surface; a first bearing member removably coupledto the first leg, the first bearing member including a first laterallyfacing bearing surface rotatably contacting the first bearing surface;and a second bearing member removably coupled to the second leg, thesecond bearing member including a second laterally facing bearingsurface rotatably contacting the second bearing surface, wherein thefirst laterally facing bearing surface is disposed between the first legand a first lateral side of the second stem, and the second laterallyfacing bearing surface is disposed between the second leg and a secondlateral side of the second stem, the second lateral side opposing thefirst lateral side.
 2. The joint prosthesis of claim 1, furthercomprising first and second fasteners for securing the second stemstructure relative to the first and second legs, respectively, forrotation about an axis of rotation.
 3. The joint prosthesis of claim 2,wherein the first and second fasteners extend in first and seconddirections, respectively, and wherein the first and second directionsare substantially perpendicular to the axis of rotation.
 4. The jointprosthesis of claim 2, wherein the first and second fasteners extend infirst and second directions, respectively, and wherein the firstdirection is substantially parallel to the second direction.
 5. Thejoint prosthesis of claim 1, wherein the first and second fastenersinterconnect the first and second bearing members to the first andsecond legs, respectively.
 6. The joint prosthesis of claim 2, whereinthe joint prosthesis is an elbow prosthesis.
 7. The elbow prosthesis ofclaim 6, wherein the first stem structure includes a proximal portiondefining a stem member adapted to fit within a medullary canal of ahumerus.
 8. The elbow prosthesis of claim 7, wherein the second stemstructure includes a distal portion adapted to fit within a medullarycanal of an ulna.
 9. An elbow prosthesis comprising: a first stemstructure including first and second spaced apart furcations; a secondstem structure having an end disposed between the first and secondspaced apart furcations, the second stem structure coupled to the firststem structure for rotation about an axis of rotation, the end includingfirst and second bearing surfaces; first and second bearing memberscarried by the first and second spaced apart furcations, respectively,the first and second bearing members disposed to articulate with thefirst and second bearing surfaces, respectively; and first and secondfasteners securing the first and second bearing members to the first andsecond spaced apart furcations, respectively, the first and secondfasteners both extending along fastener axes perpendicular to the axisof rotation.
 10. The elbow prosthesis of claim 9, wherein the fasteneraxes are substantially parallel to each other.
 11. The elbow prosthesisof claim 9, wherein the second stem structure includes an aperturehaving a central axis generally aligned with the axis of rotation. 12.The elbow prosthesis of claim 9, wherein the first bearing member isdisposed on a first lateral side of the second stem structure, and thesecond bearing member disposed on a second lateral side of the secondstem structure.
 13. The elbow prosthesis of claim 9, wherein the firstand second fasteners engage first and second apertures, respectively,the first and second apertures being in the first and second arms,respectively.
 14. The elbow prosthesis of claim 13, wherein the firstand second fasteners pass through respective openings in the first andsecond bearing members.
 15. An elbow prosthesis comprising: a first stemstructure including a proximal portion defining a stem member and adistal portion having a first leg and a second leg, the first legincluding a first aperture, and the second leg including a secondaperture; a first bearing member carried by the first leg; a secondbearing member carried by the second leg; a second stem structure; anaxle extending between the first and second bearing members and througha laterally extending opening in the distal portion of the stemstructure such that the first stem structure is connected to the secondstem structure for rotation about the axle; and a first fastenerdisposed in the first aperture and a second fastener disposed in thesecond aperture, the first and second fasteners securing the first stemstructure to the second stem structure, wherein the first and secondfasteners both extend perpendicular to the axis of rotation.
 16. Theelbow prosthesis of claim 15, wherein the first fastener is disposed ona first lateral side of the second stem structure and the secondfastners is disposed on a second lateral side of the second stemstructure.
 17. The elbow prosthesis of claim 15, wherein the first andsecond fasteners secure the first and second bearing members,respectively, to the first stem structure.
 18. A method of assembling ajoint prosthesis having a first stem structure and a second stemstructure, the first stem structure including a first leg and a secondleg, the method comprising: positioning a first bearing member betweenthe first leg and the second stem structure; positioning a secondbearing between the second leg and the second stem structure; rotatablycoupling the first stem structure to the second stem structure forrotation about an axis of rotation; securing the first stem structure tothe second stem structure with a first fastener and a second fastener,the first and second fasteners both extending perpendicular to the axisof rotation.
 19. The method of claim 18, wherein the step of securingthe first stem structure to the second stem structure is after the stepof rotatably coupling the first stem structure to the second stemstructure.
 20. The method of claim 18, wherein the step of rotatablycoupling the first stem structure to the second stem structure includesextending an axle between the first and second bearing members andthrough an end of the second stem structure.